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 | Tags: 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}
}
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 | Tags: 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
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 | Tags: 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 | Tags: General Engineering, General Materials Science, General Physics and Astronomy, Nanoscience, Nanotechnology
@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},
urldate = {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, Nanoscience, Nanotechnology},
pubstate = {published},
tppubtype = {article}
}
2020
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 | Tags: 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 | Tags: 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}
}
2019
C (Trovatello Trovatello, Chiara) ; Miranda
Strong Exciton-Coherent Phonon Coupling In Single-Layer MoS2 Proceedings Article
In: LASERS, 2019 CONFERENCE ON; (CLEO), ELECTRO-OPTICS (Ed.): Conference on Lasers and Electro-Optics, 2019, ISBN: 978-1-943580-57-6; ISSN 2160-9020.
Abstract | Links | BibTeX | Tags: Applied, Electric & Electronic, General Engineering, Optics, Physics
@inproceedings{nokey,
title = {Strong Exciton-Coherent Phonon Coupling In Single-Layer MoS2},
author = {Trovatello, C (Trovatello, Chiara) ; Miranda, HPC (Miranda, Henrique P. C.) ; Molina-Sánchez, A (Molina-Sanchez, Alejandro) ; Varillas, RB (Varillas, Rocio Borrego) ; Moretti, L (Moretti, Luca) ; Ganzer, L (Ganzer, Lucia) ; Maiuri, M (Maiuri, Margherita) ; Soavi, G (Soavi, Giancarlo) ; Ferrari, AC (Ferrari, Andrea C.) ; Marini, A (Marini, Andrea) ; Wirtz, L (Wirtz, Ludger) ; Cerullo, G (Cerullo, Giulio) ; Sangalli, D (Sangalli, Davide) ; Dal Conte, S (Dal Conte, Stefano)},
editor = {2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)},
url = {https://www.webofscience.com/wos/woscc/summary/6adb417d-7241-4ee4-a70c-46a96938e0e3-014078f410/relevance/1},
isbn = {978-1-943580-57-6; ISSN 2160-9020},
year = {2019},
date = {2019-09-09},
urldate = {2019-09-09},
booktitle = {Conference on Lasers and Electro-Optics},
abstract = {We use broadband optical pump-probe spectroscopy to study coherent optical phonons in 1L-MoS2. We detect a strong coupling with the A'(1) mode, which is enhanced around the C-exciton peak. Ab-initio calculations of the phonon-induced band structure variation fully confirm this result.},
keywords = {Applied, Electric & Electronic, General Engineering, Optics, Physics},
pubstate = {published},
tppubtype = {inproceedings}
}
We use broadband optical pump-probe spectroscopy to study coherent optical phonons in 1L-MoS2. We detect a strong coupling with the A'(1) mode, which is enhanced around the C-exciton peak. Ab-initio calculations of the phonon-induced band structure variation fully confirm this result.
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 | Tags: 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}
}
