Phonon-Enabled Carrier Transport of Localized States at Non-Polar Semiconductor Surfaces: A First-Principles-Based Prediction

Electron-phonon coupling can hamper carrier transport either by scattering or by the formation of mass-enhanced polarons. Here, we use time-dependent density functional theory-molecular dynamics simulations to show that phonons can also promote the transport of excited carriers. Using nonpolar InAs (110) surface as an example, we identify phonon-mediated coupling between electronic states close in energy as the origin for the enhanced transport. In particular, the coupling causes localized excitons in the resonant surface states to propagate into bulk with velocities as high as 10⁶ cm/s. The theory also predicts temperature enhanced carrier transport, which may be observable in ultrathin nanostructures.