Non-adiabatic quantum dynamics of tribovoltaic effects at sliding metal-semiconductor interfaces

Recent experiments observe electric current generation at sliding metal-semiconductor interfaces. Here, we present a detailed theoretical study on how electric voltage is generated at such a sliding interface. Our study is based on a two-band Anderson-Holstein model, where we solve the coupled electron-phonon dynamics using a surface hopping method. We show that the high local temperature induced by mechanical motion at the interfaces can lead to electron-hole pair generation through electron-phonon couplings. We quantify the efficiency of electron-hole generation as well as electric voltage as a function of local temperatures and semiconductor bandgaps. We find that increasing the local temperatures can lead to higher electron-hole generation and electric voltage. Furthermore, we find that there is a turnover for the electric voltage as a function of the bandgap. Such an observation is in agreement with the experimental results. Our study offers a theoretical framework to understand tribovoltaic effects from a quantum mechanical point of view, and our approach can be used to quantitatively simulate realistic sliding metal-semiconductor junctions.