Control of intervalley scattering in Bi$_2$Te$_3$ via temperature-dependent band renormalization

TL;DR

This study demonstrates that temperature-induced band structure renormalization in Bi$_2$Te$_3$ significantly influences electron scattering processes, offering a new way to control electron dynamics in topological insulators for quantum technologies.

Contribution

We reveal how modest temperature-dependent band renormalization affects electron scattering, providing a novel method to control out-of-equilibrium electron dynamics in topological insulators.

Findings

Temperature causes a ~15 meV band renormalization in Bi$_2$Te$_3$.

Band renormalization modulates intervalley electron-phonon scattering rates.

Temperature acts as a control parameter for electron scattering pathways.

Abstract

The control of out-of-equilibrium electron dynamics in topological insulators is essential to unlock their potential in next-generation quantum technologies. However, the role of temperature on the renormalization of the electronic band structure and, consequently, on electron scattering processes is still elusive. Here, using high-resolution time- and angle-resolved photoemission spectroscopy (TR-ARPES), we show that even a modest ($\sim$15 meV) renormalization of the conduction band of Bi$_2$Te$_3$ can critically affect bulk and surface electron scattering processes. Supported by a kinetic Monte Carlo toy-model, we show that temperature-induced changes in the bulk band structure modulate the intervalley electron-phonon scattering rate, reshaping the out-of-equilibrium response. This work establishes temperature as an effective control knob for engineering scattering pathways in topological insulators.