2023
Marini, Andrea
Equilibrium and out-of-equilibrium realistic phonon self-energy free from overscreening Journal Article
In: Phys. Rev. B, vol. 107, iss. 2, 2023.
Links | BibTeX | Tag: General Engineering
@article{Marini2023,
title = {Equilibrium and out-of-equilibrium realistic phonon self-energy free from overscreening},
author = {Andrea Marini},
url = {http://doi.org/10.1103/PhysRevB.107.024305},
doi = {10.1103/PhysRevB.107.024305},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Phys. Rev. B},
volume = {107},
issue = {2},
keywords = {General Engineering},
pubstate = {published},
tppubtype = {article}
}
Smejkal, Valerie; Trovatello, Chiara; Li, Qiuyang; Conte, Stefano Dal; Marini, Andrea; Zhu, Xiaoyang; Cerullo, Giulio; Libisch, Florian
Photonic effects in the non-equilibrium optical response of two-dimensional semiconductors Journal Article
In: Opt. Express, vol. 31, no 1, 2023, ISSN: 1094-4087.
Abstract | Links | BibTeX | Tag: and Optics, Atomic and Molecular Physics
@article{Smejkal2022,
title = {Photonic effects in the non-equilibrium optical response of two-dimensional semiconductors},
author = {Valerie Smejkal and Chiara Trovatello and Qiuyang Li and Stefano Dal Conte and Andrea Marini and Xiaoyang Zhu and Giulio Cerullo and Florian Libisch},
doi = {10.1364/oe.479518},
issn = {1094-4087},
year = {2023},
date = {2023-00-00},
journal = {Opt. Express},
volume = {31},
number = {1},
publisher = {Optica Publishing Group},
abstract = {<jats:p>Transient absorption spectroscopy is a powerful tool to monitor the out-of-equilibrium optical response of photoexcited semiconductors. When this method is applied to two-dimensional semiconductors deposited on different substrates, the excited state optical properties are inferred from the pump-induced changes in the transmission/reflection of the probe, <jats:italic>i.e.</jats:italic>, Δ<jats:italic>T</jats:italic>/<jats:italic>T</jats:italic> or Δ<jats:italic>R</jats:italic>/<jats:italic>R</jats:italic>. Transient optical spectra are often interpreted as the manifestation of the intrinsic optical response of the monolayer, including effects such as the reduction of the exciton oscillator strength, electron-phonon coupling or many-body interactions like bandgap renormalization, trion or biexciton formation. Here we scrutinize the assumption that one can determine the non-equilibrium optical response of the TMD without accounting for the substrate used in the experiment. We systematically investigate the effect of the substrate on the broadband transient optical response of monolayer MoS<jats:sub>2</jats:sub> (1L-MoS<jats:sub>2</jats:sub>) by measuring Δ<jats:italic>T</jats:italic>/<jats:italic>T</jats:italic> and Δ<jats:italic>R</jats:italic>/<jats:italic>R</jats:italic> with different excitation photon energies. Employing the boundary conditions given by the Fresnel equations, we analyze the transient transmission/reflection spectra across the main excitonic resonances of 1L-MoS<jats:sub>2</jats:sub>. We show that pure interference effects induced by the different substrates explain the substantial differences (<jats:italic>i.e.</jats:italic>, intensity, peak energy and exciton linewidth) observed in the transient spectra of the same monolayer. We thus demonstrate that the substrate strongly affects the magnitude of the exciton energy shift and the change of the oscillator strength in the transient optical spectra. By highlighting the key role played by the substrate, our results set the stage for a unified interpretation of the transient response of optoelectronic devices based on a broad class of TMDs.</jats:p>},
keywords = {and Optics, Atomic and Molecular Physics},
pubstate = {published},
tppubtype = {article}
}
<jats:p>Transient absorption spectroscopy is a powerful tool to monitor the out-of-equilibrium optical response of photoexcited semiconductors. When this method is applied to two-dimensional semiconductors deposited on different substrates, the excited state optical properties are inferred from the pump-induced changes in the transmission/reflection of the probe, <jats:italic>i.e.</jats:italic>, Δ<jats:italic>T</jats:italic>/<jats:italic>T</jats:italic> or Δ<jats:italic>R</jats:italic>/<jats:italic>R</jats:italic>. Transient optical spectra are often interpreted as the manifestation of the intrinsic optical response of the monolayer, including effects such as the reduction of the exciton oscillator strength, electron-phonon coupling or many-body interactions like bandgap renormalization, trion or biexciton formation. Here we scrutinize the assumption that one can determine the non-equilibrium optical response of the TMD without accounting for the substrate used in the experiment. We systematically investigate the effect of the substrate on the broadband transient optical response of monolayer MoS<jats:sub>2</jats:sub> (1L-MoS<jats:sub>2</jats:sub>) by measuring Δ<jats:italic>T</jats:italic>/<jats:italic>T</jats:italic> and Δ<jats:italic>R</jats:italic>/<jats:italic>R</jats:italic> with different excitation photon energies. Employing the boundary conditions given by the Fresnel equations, we analyze the transient transmission/reflection spectra across the main excitonic resonances of 1L-MoS<jats:sub>2</jats:sub>. We show that pure interference effects induced by the different substrates explain the substantial differences (<jats:italic>i.e.</jats:italic>, intensity, peak energy and exciton linewidth) observed in the transient spectra of the same monolayer. We thus demonstrate that the substrate strongly affects the magnitude of the exciton energy shift and the change of the oscillator strength in the transient optical spectra. By highlighting the key role played by the substrate, our results set the stage for a unified interpretation of the transient response of optoelectronic devices based on a broad class of TMDs.</jats:p>
2022
Fulvio Paleari, Andrea Marini
Exciton-phonon interaction calls for a revision of the “exciton” concept Journal Article
In: Physical Review B, vol. 106, iss. 12, pp. 125403, 2022.
Abstract | Links | BibTeX | Tag: and Optics, Atomic and Molecular Physics, General Engineering, General Materials Science, General Physics and Astronomy
@article{,
title = {Exciton-phonon interaction calls for a revision of the “exciton” concept},
author = {Fulvio Paleari, Andrea Marini},
editor = {American Physical Society},
url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.106.125403
},
doi = {https://doi.org/10.1103/PhysRevB.106.125403},
year = {2022},
date = {2022-09-15},
urldate = {2022-09-15},
journal = {Physical Review B},
volume = {106},
issue = {12},
pages = {125403},
abstract = {The concept of optical exciton—a photoexcited bound electron-hole pair within a crystal—is routinely used to interpret and model a wealth of excited-state phenomena in semiconductors. Beside originating subband gap signatures in optical spectra, optical excitons have also been predicted to condensate, diffuse, recombine, and relax. However, all these phenomena are rooted on a theoretical definition of the excitonic state based on the following simple picture: “excitons” are actual particles that both appear as peaks in the linear absorption spectrum and also behave as well-defined quasiparticles. In this paper, we show, instead, that the electron–phonon interaction decomposes the initial optical (i.e., “reducible”) excitons into elemental (i.e., “irreducible”) excitons, the latter being a different kind of bound electron-hole pairs lacking the effect caused by the induced, classical, electric field. This is demonstrated within a real-time, many-body perturbation theory approach starting from the interacting electronic Hamiltonian including both electron-phonon and electron-hole interactions. We then apply the results to two realistic and paradigmatic systems, monolayer MoS2 (where the lowest-bound optical exciton is optically inactive) and monolayer MoSe2 (where it is optically active), using first-principles methods to compute the exciton-phonon coupling matrix elements. Among the consequences of optical-elemental decomposition, we point to a homogeneous broadening of absorption peaks occurring even for the lowest-bound optical exciton , and we demonstrate this by computing exciton-phonon transition rates. More generally, our findings suggest that the optical excitons gradually lose their initial structure and evolve as elemental excitons. These states can be regarded as the real intrinsic excitations of the interacting system, the ones that survive when the external perturbation and the induced electric fields have vanished.},
keywords = {and Optics, Atomic and Molecular Physics, General Engineering, General Materials Science, General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}
The concept of optical exciton—a photoexcited bound electron-hole pair within a crystal—is routinely used to interpret and model a wealth of excited-state phenomena in semiconductors. Beside originating subband gap signatures in optical spectra, optical excitons have also been predicted to condensate, diffuse, recombine, and relax. However, all these phenomena are rooted on a theoretical definition of the excitonic state based on the following simple picture: “excitons” are actual particles that both appear as peaks in the linear absorption spectrum and also behave as well-defined quasiparticles. In this paper, we show, instead, that the electron–phonon interaction decomposes the initial optical (i.e., “reducible”) excitons into elemental (i.e., “irreducible”) excitons, the latter being a different kind of bound electron-hole pairs lacking the effect caused by the induced, classical, electric field. This is demonstrated within a real-time, many-body perturbation theory approach starting from the interacting electronic Hamiltonian including both electron-phonon and electron-hole interactions. We then apply the results to two realistic and paradigmatic systems, monolayer MoS2 (where the lowest-bound optical exciton is optically inactive) and monolayer MoSe2 (where it is optically active), using first-principles methods to compute the exciton-phonon coupling matrix elements. Among the consequences of optical-elemental decomposition, we point to a homogeneous broadening of absorption peaks occurring even for the lowest-bound optical exciton , and we demonstrate this by computing exciton-phonon transition rates. More generally, our findings suggest that the optical excitons gradually lose their initial structure and evolve as elemental excitons. These states can be regarded as the real intrinsic excitations of the interacting system, the ones that survive when the external perturbation and the induced electric fields have vanished.
2021
Davide Sangalli Federico Pressacco, Vojtěch Uhlíř
Subpicosecond metamagnetic phase transition in FeRh driven by non-equilibrium electron dynamics Journal Article
In: Nature Communications, vol. 12, iss. 1, pp. 5088, 2021, ISSN: 2041-1723 (online).
Abstract | Links | BibTeX | Tag:
@article{nokey,
title = {Subpicosecond metamagnetic phase transition in FeRh driven by non-equilibrium electron dynamics},
author = {Federico Pressacco, Davide Sangalli, Vojtěch Uhlíř, Dmytro Kutnyakhov, Jon Ander Arregi, Steinn Ymir Agustsson, Günter Brenner, Harald Redlin, Michael Heber, Dmitry Vasilyev, Jure Demsar, Gerd Schönhense, Matteo Gatti, Andrea Marini, Wilfried Wurth, Fausto Sirotti},
editor = {Nature Publishing Group UK},
url = {https://rdcu.be/d4hLP},
doi = {https://doi.org/10.1038/s41467-021-25347-3},
issn = {2041-1723 (online)},
year = {2021},
date = {2021-08-24},
journal = {Nature Communications},
volume = {12},
issue = {1},
pages = {5088},
abstract = {Femtosecond light-induced phase transitions between different macroscopic orders provide the possibility to tune the functional properties of condensed matter on ultrafast timescales. In first-order phase transitions, transient non-equilibrium phases and inherent phase coexistence often preclude non-ambiguous detection of transition precursors and their temporal onset. Here, we present a study combining time-resolved photoelectron spectroscopy and ab-initio electron dynamics calculations elucidating the transient subpicosecond processes governing the photoinduced generation of ferromagnetic order in antiferromagnetic FeRh. The transient photoemission spectra are accounted for by assuming that not only the occupation of electronic states is modified during the photoexcitation process. Instead, the photo-generated non-thermal distribution of electrons modifies the electronic band structure. The ferromagnetic phase of FeRh, characterized by a minority band near the Fermi energy, is established 350 ± 30 fs after the laser excitation. Ab-initio calculations indicate that the phase transition is initiated by a photoinduced Rh-to-Fe charge transfer.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Femtosecond light-induced phase transitions between different macroscopic orders provide the possibility to tune the functional properties of condensed matter on ultrafast timescales. In first-order phase transitions, transient non-equilibrium phases and inherent phase coexistence often preclude non-ambiguous detection of transition precursors and their temporal onset. Here, we present a study combining time-resolved photoelectron spectroscopy and ab-initio electron dynamics calculations elucidating the transient subpicosecond processes governing the photoinduced generation of ferromagnetic order in antiferromagnetic FeRh. The transient photoemission spectra are accounted for by assuming that not only the occupation of electronic states is modified during the photoexcitation process. Instead, the photo-generated non-thermal distribution of electrons modifies the electronic band structure. The ferromagnetic phase of FeRh, characterized by a minority band near the Fermi energy, is established 350 ± 30 fs after the laser excitation. Ab-initio calculations indicate that the phase transition is initiated by a photoinduced Rh-to-Fe charge transfer.
A Molina-Sánchez M Marsili, M Palummo
Spinorial formulation of the -BSE equations and spin properties of excitons in two-dimensional transition metal dichalcogenides Journal Article
In: Physical Review B, vol. 103, iss. 15, pp. 155152, 2021, ISSN: 2469-9969 (online), 2469-9950 (print).
Abstract | Links | BibTeX | Tag: and Optics, Atomic and Molecular Physics, General Engineering, General Materials Science, General Physics and Astronomy
@article{nokey,
title = {Spinorial formulation of the -BSE equations and spin properties of excitons in two-dimensional transition metal dichalcogenides},
author = {M Marsili, A Molina-Sánchez, M Palummo, D Sangalli, A Marini},
editor = {American Physical Society},
url = {https://journals.aps.org/prb/pdf/10.1103/PhysRevB.103.155152},
doi = { https://doi.org/10.1103/PhysRevB.103.155152},
issn = {2469-9969 (online), 2469-9950 (print)},
year = {2021},
date = {2021-04-15},
journal = {Physical Review B},
volume = {103},
issue = {15},
pages = {155152},
abstract = {In many paradigmatic materials, such as transition metal dichalcogenides, the role played by the spin degrees of freedom is as important as the one played by the electron-electron interaction. Thus an accurate treatment of the two effects and of their interaction is necessary for an accurate and predictive study of the optical and electronic properties of these materials. Despite the fact that the GW-BSE approach correctly accounts for electronic correlations, the spin-orbit coupling effect is often neglected or treated perturbatively. Recently, spinorial formulations of GW-BSE have become available in different flavors in material-science codes. However, an accurate validation and comparison of different approaches is still missing. In this work, we go through the derivation of the noncollinear GW-BSE approach. The scheme is applied to transition metal dichalcogenides comparing the perturbative and full spinorial approaches. Our calculations reveal that dark-bright exciton splittings are generally improved when the spin-orbit coupling is included nonperturbatively. The exchange-driven intravalley mixing between the A and B excitons is found to play a role for Mo-based systems, being especially strong in the case of MoSe2. We finally compute the excitonic spin and use it to sharply analyze the spinorial properties of transition metal dichalcogenide excitonic states.},
keywords = {and Optics, Atomic and Molecular Physics, General Engineering, General Materials Science, General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}
In many paradigmatic materials, such as transition metal dichalcogenides, the role played by the spin degrees of freedom is as important as the one played by the electron-electron interaction. Thus an accurate treatment of the two effects and of their interaction is necessary for an accurate and predictive study of the optical and electronic properties of these materials. Despite the fact that the GW-BSE approach correctly accounts for electronic correlations, the spin-orbit coupling effect is often neglected or treated perturbatively. Recently, spinorial formulations of GW-BSE have become available in different flavors in material-science codes. However, an accurate validation and comparison of different approaches is still missing. In this work, we go through the derivation of the noncollinear GW-BSE approach. The scheme is applied to transition metal dichalcogenides comparing the perturbative and full spinorial approaches. Our calculations reveal that dark-bright exciton splittings are generally improved when the spin-orbit coupling is included nonperturbatively. The exchange-driven intravalley mixing between the A and B excitons is found to play a role for Mo-based systems, being especially strong in the case of MoSe2. We finally compute the excitonic spin and use it to sharply analyze the spinorial properties of transition metal dichalcogenide excitonic states.
Smejkal, Valerie; Libisch, Florian; Molina-Sanchez, Alejandro; Trovatello, Chiara; Wirtz, Ludger; Marini, Andrea
Time-Dependent Screening Explains the Ultrafast Excitonic Signal Rise in 2D Semiconductors Journal Article
In: ACS Nano, vol. 15, no 1, pp. 1179–1185, 2021, ISSN: 1936-086X.
Links | BibTeX | Tag: General Engineering, General Materials Science, General Physics and Astronomy
@article{Smejkal2020,
title = {Time-Dependent Screening Explains the Ultrafast Excitonic Signal Rise in 2D Semiconductors},
author = {Valerie Smejkal and Florian Libisch and Alejandro Molina-Sanchez and Chiara Trovatello and Ludger Wirtz and Andrea Marini},
doi = {10.1021/acsnano.0c08173},
issn = {1936-086X},
year = {2021},
date = {2021-01-26},
journal = {ACS Nano},
volume = {15},
number = {1},
pages = {1179–1185},
publisher = {American Chemical Society (ACS)},
keywords = {General Engineering, General Materials Science, General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}
2020
Mauro Del Ben c Tonatiuh Rangel, Daniele Varsano
Reproducibility in G0W0 calculations for solids Journal Article
In: Computer Physics Communications, vol. 255, pp. 107242, 2020, ISSN: 0010-4655 Online ISSN: 1879-2944.
Abstract | Links | BibTeX | Tag:
@article{nokey,
title = {Reproducibility in G0W0 calculations for solids},
author = {Tonatiuh Rangel, Mauro Del Ben c, Daniele Varsano, Gabriel Antonius,
Fabien Bruneval, Felipe H. da Jornada, Michiel J. van Setten, Okan K. Orhan,
David D. O’Regan, Andrew Canning, Andrea Ferretti, Andrea Marini, Gian-Marco Rignanese, Jack Deslippe, Steven G. Louie, Jeffrey B. Neaton },
editor = {North-Holland},
url = {https://pdf.sciencedirectassets.com/271575/1-s2.0-S0010465520X00087/1-s2.0-S0010465520300734/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEMT%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaCXVzLWVhc3QtMSJHMEUCIQCF62nE7DuRrBWT%2FbMLddOBRtwfDGMxZhOAo3QXvLlqgAIgPuG6RLu73dbkiuWBGB51Vto7BQ4w60RZ%2Fe%2Bf22O68EAqvAUIjf%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAFGgwwNTkwMDM1NDY4NjUiDDUSjbHss2oVx8Gd0yqQBZDggwV1lFmO8gLG3HzHJeXqImbX945LdX1eQ1A8OC4RHA2f2WpIh%2Fp%2B3UQKAR22bOUsHsnG1NH%2FZXTLrJUQfVaHVuDS9DewckxpJZrRLHWZBizNeVx2zfoRb30V1uMxaPkldogzOXmND0iXVj3f%2FLOk4kYmHwDSy4QcgBx3z5lwNfDA2nm86zS1CNRHylHO2extm5I9Imbqeylr7kJKvdyPy2iZYsdjdGv59Vyc4bMtVHfXprtfJZGaOZx7%2BzLWsAlrSnfoDZktRASJ4xZNOoD6cIlQ%2FG7JSwPhgPVmwXLEBDEnGP5G1I4XX0kRZECBIVBZujmtLdm2mkLiG3oAfK8uUU60PEB%2BupCGGEt33bfFlLJNFR4TyfzUbebYTUOKbhbiRQTyNOKoq0PnWltNgSN8fJMmxpAsxqObgIh%2FUYH4IoMd%2B2faDDzOfXXAW69yUgReQW9EACBZpM7fqz0ijroE6csOV8Ol9sRNwp122WVATQICX8LCR9SOwz10u%2FlJezTPD2pCzGEWRwbNvD9PDs4iIXuBYChq5oBwXnNU3UjZd8hIDCobu06s06Qf6iZLpPo1YILHFMW6jVK89KVWmmF%2FSbaNs22R%2B%2Ba3jXZ2L%2FOeRsvle46cWx%2BmVM9STdZ8s5nIt0R4X8239ckXZ2w81Sy%2BtwSFBJgCIY4YfxHhA5f3lDj4god0JfFR5zj6iobUhUvTvr%2FUwZ4QFNdWwdYdtbJE88i19hbSqxyFWrKh%2FQbuldSzy1aiJSO2wz4xhycQmjf7z3cMrYGdoaMM7As4XZDf2zVKqTsE8no0m66DPen437kZP0pDm2VfdEttrgMpWtKVGmLIQ5I1dsY4O4p9WCWbwLFm8AXF499SAuh0WVoyMOG2lbsGOrEBtOnHz%2BQ1LXV4k3pAdTXOBxEedUuaAot%2B1%2Bqg1e7bo%2F9eKjK%2BxjFZdYxslyUELY%2B3%2F2ib9X3O1bvY5J%2FQHrrQ56G1CjQW%2FyLj%2BoOd0n5z4DrG%2By3DATiAmoo%2FQOn3X3ui0etP0YvD%2F2AnxA0EwzCRS4cZNJWcISTkrnc%2BM2mQv7xKmyUxD8Y1VytN8rMKpPys8jZmDb4j2hK2bw6OmUFY9c3PlcuQcKnaY13vaIDhp1Rk&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20241220T125646Z&X-Amz-SignedHeaders=host&X-Amz-Expires=300&X-Amz-Credential=ASIAQ3PHCVTY2G6IKVKY%2F20241220%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=692d0668e88e372f4eaa2866333e9dc69ed37841dec1d2530bf21ff77c1f60cd&hash=782468c9e6ad2e088f0365acb7557bb8c973520d6d4e552cc03d10bb2dc4800d&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S0010465520300734&tid=spdf-44500ee1-caf8-49f9-969a-da76435bddf2&sid=974eba3a12cac047a93b839143f879094241gxrqb&type=client&tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&ua=0f145e0252040c07565b&rr=8f4fcb58aa1ef940&cc=it},
doi = {https://doi.org/10.1016/j.cpc.2020.107242},
issn = {0010-4655 Online ISSN: 1879-2944},
year = {2020},
date = {2020-10-01},
urldate = {2020-10-01},
journal = {Computer Physics Communications},
volume = {255},
pages = {107242},
abstract = {Ab initio many-body perturbation theory within the GW approximation is a Green’s function formalism
widely used in the calculation of quasiparticle excitation energies of solids. In what has become an
increasingly standard approach, Kohn–Sham eigenenergies, generated from a DFT calculation with a
strategically-chosen exchange–correlation functional ‘‘starting point’’, are used to construct G and W,
and then perturbatively corrected by the resultant GW self-energy. In practice, there are several ways
to construct the GW self-energy, and these can lead to variations in predicted quasiparticle energies.
For example, for ZnO and TiO2, the GW fundamental gaps reported in the literature can vary by more
than 1 eV depending on the GW code used. In this work, we calculate and analyze GW quasiparticle
(QP) energies of these and other systems with three different GW codes: BerkeleyGW, Abinit and
Yambo. Through a systematic analysis of the GW implementation of these three codes, we identify the
primary origin of major discrepancies between codes reported in prior literature to be the different
implementations the Coulomb divergence in the Fock exchange term and the frequency integration
scheme of the GW self-energy. We then eliminate these discrepancies by using common numerical
methods and algorithms, demonstrating that the same quasiparticle energies for a given material can
be obtained with different codes, within numerical differences ascribable to the technical details of
the underling implementations. This work will be important for users and developers in assessing the
precision of future GW applications and methods.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ab initio many-body perturbation theory within the GW approximation is a Green’s function formalism
widely used in the calculation of quasiparticle excitation energies of solids. In what has become an
increasingly standard approach, Kohn–Sham eigenenergies, generated from a DFT calculation with a
strategically-chosen exchange–correlation functional ‘‘starting point’’, are used to construct G and W,
and then perturbatively corrected by the resultant GW self-energy. In practice, there are several ways
to construct the GW self-energy, and these can lead to variations in predicted quasiparticle energies.
For example, for ZnO and TiO2, the GW fundamental gaps reported in the literature can vary by more
than 1 eV depending on the GW code used. In this work, we calculate and analyze GW quasiparticle
(QP) energies of these and other systems with three different GW codes: BerkeleyGW, Abinit and
Yambo. Through a systematic analysis of the GW implementation of these three codes, we identify the
primary origin of major discrepancies between codes reported in prior literature to be the different
implementations the Coulomb divergence in the Fock exchange term and the frequency integration
scheme of the GW self-energy. We then eliminate these discrepancies by using common numerical
methods and algorithms, demonstrating that the same quasiparticle energies for a given material can
be obtained with different codes, within numerical differences ascribable to the technical details of
the underling implementations. This work will be important for users and developers in assessing the
precision of future GW applications and methods.
widely used in the calculation of quasiparticle excitation energies of solids. In what has become an
increasingly standard approach, Kohn–Sham eigenenergies, generated from a DFT calculation with a
strategically-chosen exchange–correlation functional ‘‘starting point’’, are used to construct G and W,
and then perturbatively corrected by the resultant GW self-energy. In practice, there are several ways
to construct the GW self-energy, and these can lead to variations in predicted quasiparticle energies.
For example, for ZnO and TiO2, the GW fundamental gaps reported in the literature can vary by more
than 1 eV depending on the GW code used. In this work, we calculate and analyze GW quasiparticle
(QP) energies of these and other systems with three different GW codes: BerkeleyGW, Abinit and
Yambo. Through a systematic analysis of the GW implementation of these three codes, we identify the
primary origin of major discrepancies between codes reported in prior literature to be the different
implementations the Coulomb divergence in the Fock exchange term and the frequency integration
scheme of the GW self-energy. We then eliminate these discrepancies by using common numerical
methods and algorithms, demonstrating that the same quasiparticle energies for a given material can
be obtained with different codes, within numerical differences ascribable to the technical details of
the underling implementations. This work will be important for users and developers in assessing the
precision of future GW applications and methods.
R Patrick Xian Maciej Dendzik, Enrico Perfetto
Observation of an Excitonic Mott Transition through Ultrafast Core-cum-Conduction Photoemission Spectroscopy Journal Article
In: Physical review letters, vol. 125, iss. 9, pp. 096401, 2020, ISSN: 1079-7114 (online), 0031-9007 (print).
Abstract | Links | BibTeX | Tag: and Optics, Atomic and Molecular Physics, General Engineering, General Materials Science, General Physics and Astronomy
@article{nokey,
title = {Observation of an Excitonic Mott Transition through Ultrafast Core-cum-Conduction Photoemission Spectroscopy},
author = {Maciej Dendzik, R Patrick Xian, Enrico Perfetto, Davide Sangalli, Dmytro Kutnyakhov, Shuo Dong, Samuel Beaulieu, Tommaso Pincelli, Federico Pressacco, Davide Curcio, Steinn Ymir Agustsson, Michael Heber, Jasper Hauer, Wilfried Wurth, Günter Brenner, Yves Acremann, Philip Hofmann, Martin Wolf, Andrea Marini, Gianluca Stefanucci, Laurenz Rettig, Ralph Ernstorfer},
editor = {American Physical Society},
url = {https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.125.096401},
doi = {https://doi.org/10.1103/PhysRevLett.125.096401},
issn = {1079-7114 (online), 0031-9007 (print)},
year = {2020},
date = {2020-08-28},
urldate = {2020-08-28},
journal = {Physical review letters},
volume = {125},
issue = {9},
pages = {096401},
abstract = {Time-resolved soft-x-ray photoemission spectroscopy is used to simultaneously measure the ultrafast dynamics of core-level spectral functions and excited states upon excitation of excitons in WSe2. We present a many-body approximation for the Green’s function, which excellently describes the transient core-hole spectral function. The relative dynamics of excited-state signal and core levels clearly show a delayed core-hole renormalization due to screening by excited quasifree carriers resulting from an excitonic Mott transition. These findings establish time-resolved core-level photoelectron spectroscopy as a sensitive probe of subtle electronic many-body interactions and ultrafast electronic phase transitions.},
keywords = {and Optics, Atomic and Molecular Physics, General Engineering, General Materials Science, General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}
Time-resolved soft-x-ray photoemission spectroscopy is used to simultaneously measure the ultrafast dynamics of core-level spectral functions and excited states upon excitation of excitons in WSe2. We present a many-body approximation for the Green’s function, which excellently describes the transient core-hole spectral function. The relative dynamics of excited-state signal and core levels clearly show a delayed core-hole renormalization due to screening by excited quasifree carriers resulting from an excitonic Mott transition. These findings establish time-resolved core-level photoelectron spectroscopy as a sensitive probe of subtle electronic many-body interactions and ultrafast electronic phase transitions.
Trovatello, Chiara; Miranda, Henrique P. C.; Molina-Sánchez, Alejandro; Borrego-Varillas, Rocío; Manzoni, Cristian; Moretti, Luca; Ganzer, Lucia; Maiuri, Margherita; Wang, Junjia; Dumcenco, Dumitru; Kis, Andras; Wirtz, Ludger; Marini, Andrea; Soavi, Giancarlo; Ferrari, Andrea C.; Cerullo, Giulio; Sangalli, Davide; Conte, Stefano Dal
Strongly Coupled Coherent Phonons in Single-Layer MoS_2 Journal Article
In: ACS Nano, vol. 14, no 5, pp. 5700–5710, 2020, ISSN: 1936-086X.
Links | BibTeX | Tag: General Engineering, General Materials Science, General Physics and Astronomy
@article{Trovatello2020,
title = {Strongly Coupled Coherent Phonons in Single-Layer MoS_2},
author = {Chiara Trovatello and Henrique P. C. Miranda and Alejandro Molina-Sánchez and Rocío Borrego-Varillas and Cristian Manzoni and Luca Moretti and Lucia Ganzer and Margherita Maiuri and Junjia Wang and Dumitru Dumcenco and Andras Kis and Ludger Wirtz and Andrea Marini and Giancarlo Soavi and Andrea C. Ferrari and Giulio Cerullo and Davide Sangalli and Stefano Dal Conte},
doi = {10.1021/acsnano.0c00309},
issn = {1936-086X},
year = {2020},
date = {2020-05-26},
journal = {ACS Nano},
volume = {14},
number = {5},
pages = {5700–5710},
publisher = {American Chemical Society (ACS)},
keywords = {General Engineering, General Materials Science, General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}
2016
Pogna, Eva A. A.; Marsili, Margherita; Fazio, Domenico De; Conte, Stefano Dal; Manzoni, Cristian; Sangalli, Davide; Yoon, Duhee; Lombardo, Antonio; Ferrari, Andrea C.; Marini, Andrea; Cerullo, Giulio; Prezzi, Deborah
Photo-Induced Bandgap Renormalization Governs the Ultrafast Response of Single-Layer MoS_2 Journal Article
In: ACS Nano, vol. 10, no 1, pp. 1182–1188, 2016, ISSN: 1936-086X.
Links | BibTeX | Tag: General Engineering, General Materials Science, General Physics and Astronomy
@article{Pogna2016,
title = {Photo-Induced Bandgap Renormalization Governs the Ultrafast Response of Single-Layer MoS_2},
author = {Eva A. A. Pogna and Margherita Marsili and Domenico De Fazio and Stefano Dal Conte and Cristian Manzoni and Davide Sangalli and Duhee Yoon and Antonio Lombardo and Andrea C. Ferrari and Andrea Marini and Giulio Cerullo and Deborah Prezzi},
doi = {10.1021/acsnano.5b06488},
issn = {1936-086X},
year = {2016},
date = {2016-01-26},
journal = {ACS Nano},
volume = {10},
number = {1},
pages = {1182–1188},
publisher = {American Chemical Society (ACS)},
keywords = {General Engineering, General Materials Science, General Physics and Astronomy},
pubstate = {published},
tppubtype = {article}
}