Measurement of an Exceptionally Weak Electron-Phonon Coupling on the Surface of the Topological Insulator Bi$_2$Se$_3$ Using Angle-Resolved Photoemission Spectroscopy

TL;DR

This study reveals that the topological surface states of Bi$_2$Se$_3$ exhibit exceptionally weak electron-phonon coupling, maintaining coherence at ambient temperatures, which is promising for room-temperature electronic applications.

Contribution

It provides the first detailed measurement showing extremely weak electron-phonon coupling on the surface of Bi$_2$Se$_3$ using high-resolution ARPES.

Findings

Weak temperature-dependent broadening of surface states

No anomalies in the dispersion with temperature

Protection from phonon scattering at room temperature

Abstract

Gapless surface states on topological insulators are protected from elastic scattering on non-magnetic impurities which makes them promising candidates for low-power electronic applications. However, for wide-spread applications, these states should have to remain coherent at ambient temperatures. Here, we studied temperature dependence of the electronic structure and the scattering rates on the surface of a model topological insulator, Bi$_2$Se$_3$, by high resolution angle-resolved photoemission spectroscopy. We found an extremely weak broadening of the topological surface state with temperature and no anomalies in the state's dispersion, indicating exceptionally weak electron-phonon coupling. Our results demonstrate that the topological surface state is protected not only from elastic scattering on impurities, but also from scattering on low-energy phonons, suggesting that topological insulators could serve as a basis for room temperature electronic devices.