Logarithmic singularities and quantum oscillations in magnetically doped topological insulators

TL;DR

This study investigates magnetotransport phenomena in magnetically doped topological insulator films, revealing logarithmic singularities due to disorder and electron interactions, and observing quantum oscillations linked to bulk and surface states.

Contribution

It provides new insights into the interplay of disorder, electron interactions, and quantum oscillations in magnetically doped topological insulators.

Findings

Logarithmic dependence on temperature and bias voltage in Hall resistance.

Quantitative explanation of singularities by disorder and electron-electron interactions.

Quantum oscillations at high magnetic fields related to bulk and surface transport.

Abstract

We report magnetotransport measurements on magnetically doped (Bi,Sb)$_2$Te$_3$ films grown by molecular beam epitaxy. In Hallbar devices, logarithmic dependence on temperature and bias voltage are obseved in both the longitudinal and anomalous Hall resistance. The interplay of disorder and electron-electron interactions is found to explain quantitatively the observed logarithmic singularities and is a dominant scattering mechanism in these samples. Submicron scale devices exhibit intriguing quantum oscillations at high magnetic fields with dependence on bias voltage. The observed quantum oscillations can be attributed to bulk and surface transport.