Temperature Renormalization of Optical Spectra of Monolayer MoS2
arXiv:1401.5732 · doi:10.1063/1.4878098
Abstract
Newly measured optical absorption and photoluminescence spectra reveal substantial frequency shifts of both exciton and trion peaks as monolayer MoS2 is cooled from 363 K to 4 K. First-principles simulations using the GW-Bethe-Salpeter Equation approach satisfactorily reproduce these frequency shifts by incorporating many-electron interactions and the thermal expansion of the in-plane lattice constant. Studying these temperature effects in monolayer MoS2 is crucial for rectifying the results of room-temperature experiments with the previous predictions of zero-temperature-limit simulations. Moreover, we estimate that the thermal expansion coefficient of monolayer MoS2 is around 25% less than that of bulk counterpart by tracking the frequency shifts of the exciton or trion peaks in optical spectra. This may serve as a convenient way to estimate thermal expansion coefficients of general two-dimensional chalcogenides.
12 pages and 4 figures