Role of effective mass and long-range interactions in the band-gap renormalization of photoexcited semiconductors
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1.
University of California, Santa Barbara
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2.
California Institute of Technology
Abstract
Understanding how to control changes in the electronic structure and related dynamical renormalizations by external driving fields is the key for understanding ultrafast spectroscopy and applications in electronics. Here, we focus on the band gap's modulation by external electric fields and uncover the effect of band dispersion on the gap renormalization. We employ the Green's function formalism using the real-time Dyson expansion to account for dynamical correlations induced by photodoping. The many-body formalism captures the dynamics of systems with long-range interactions, carrier mobility, and variable electron and hole effective mass. We also demonstrate that mean-field simulations based on the Hartree-Fock Hamiltonian, which lacks dynamical correlations, yields a qualitatively incorrect picture of band-gap renormalization. We find the trend that increasing effective mass, thus decreasing mobility, leads to as much as a 6% enhancement in band-gap renormalization. Further, the renormalization is strongly dependent on the degree of photodoping. As the screening induced by free electrons and holes effectively reduces any long-range and interband interactions for highly excited systems, we show that there is a specific turnover point with a minimal band gap. We further demonstrate that the optical gap renormalization follows the same trend though its magnitude is altered by the Moss-Burstein effect.
Copyright and License
©2025 American Physical Society.
Acknowledgement
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, and Office of Basic Energy Sciences, Scientific Discovery through Advanced Computing (SciDAC) program under Award No. DE-SC0022198. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC Award No. BES-ERCAP0032056. C.C.R. is supported by the National Science Foundation through Enabling Quantum Leap: Convergent Accelerated Discovery Foundries for Quantum Materials Science, Engineering and Information (Q-AMASE-i) Award No. DMR-1906325. S.K.C. is supported by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award No. DE-SC0021266.
Supplemental Material
The supplemental file is a pdf containing the following:
-Electric field values used in the various simulations
-Details on calculations used in the main text results
-additional results and calculations to further illustrate conclusions in main text
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Additional details
Funding
- Office of Basic Energy Sciences
- DE-SC0022198
- Office of Basic Energy Sciences
- Liquid Sunlight Alliance DE-SC0021266
- United States Department of Energy
- DE-AC02-05CH11231
- National Energy Research Scientific Computing Center
- BES-ERCAP0032056
- National Science Foundation
- DMR-1906325
Dates
- Available
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2025-08-04Published online