Spectral function of the Holstein polaron at finite temperature
Here we compute the Holstein polaron spectral function on a one-dimensional ring using the finite-temperature T Lanczos method. With increasing T additional features in the spectral function emerge even at temperatures below the phonon frequency. We observe a substantial spread of the spectral weight towards lower frequencies and the broadening of the quasiparticle (QP) peak. In the weak-coupling regime the QP peak merges with the continuum in the high-T limit. In the strong-coupling regime the main features of the low-T spectral function remain detectable up to the highest T used in our calculations. The effective polaron mass shows a nonmonotonic behavior as a function of T at small phonon frequency but increases with T at larger frequencies. The self-energy remains k independent even at elevated T in the frequency range corresponding to the polaron band, while at higher frequencies it develops a distinguishable k dependence. Analytical expressions for the first few frequency moments are derived, and they agree well with those extracted from numerical calculations in a wide-T regime.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Laboratory Directed Research and Development (LDRD) Program; Slovenian Research Agency; Natural Sciences and Engineering Research Council of Canada (NSERC)
- Grant/Contract Number:
- 89233218CNA000001; P1-0044
- OSTI ID:
- 1756820
- Report Number(s):
- LA-UR-20-21134; TRN: US2205682
- Journal Information:
- Physical Review. B, Vol. 100, Issue 9; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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