Electronic charge rearrangement between components of a heterostructure is the fundamental principle to reach the electronic ground state. It is acknowledged that the density of states distribution of the components governs the amount of charge transfer, but a notable dependence on temperature has not yet been considered, particularly for weakly interacting systems. Here, we experimentally observe that the amount of ground state charge transfer in a van der Waals heterostructure formed by monolayer MoS2 sandwiched between graphite and a molecular electron acceptor layer increases by a factor of three when going from 7 K to room temperature. State-of-the-art electronic structure calculations of the full heterostructure that account for nuclear thermal fluctuations reveal intra-component electron-phonon coupling and inter-component electronic coupling as the key factors determining the amount of charge transfer. This conclusion is rationalized by a model applicable to multi-component van der Waals heterostructures.
@article{arxiv.2103.07962,
title = {Temperature-dependent electronic ground state charge transfer in van der Waals heterostructures},
author = {Soohyung Park and Haiyuan Wang and Thorsten Schultz and Dongguen Shin and Ruslan Ovsyannikov and Marios Zacharias and Dmitrii Maksimov and Matthias Meissner and Yuri Hasegawa and Takuma Yamaguchi and Satoshi Kera and Areej Aljarb and Mariam Hakami and Lain-Jong Li and Vincent Tung and Patrick Amsalem and Mariana Rossi and Norbert Koch},
journal= {arXiv preprint arXiv:2103.07962},
year = {2021}
}