# Investigation of high-temperature bulk transport characteristics and skew scattering in samarium hexaboride

## TL;DR

This study extends Hall measurements of SmB$_6$ up to 400 K, revealing a temperature-dependent sign change in the Hall coefficient due to skew scattering from correlated $f$ and $d$ electrons, elucidating high-temperature transport behavior.

## Contribution

It introduces a detailed analysis of high-temperature bulk transport and skew scattering effects in SmB$_6$, linking electronic resonance to Hall coefficient sign changes.

## Key findings

- Hall coefficient changes sign at ~305 K
- Skew scattering dominates when $f$ and $d$ electrons resonate
- Transport behavior linked to electron resonance and correlations

## Abstract

A well-known feature in transport data of the topological Kondo insulator SmB$_6$ is the sign change in the Hall coefficient at 65 K. Carriers in SmB$_6$ are known to be negative, but above 65 K, the Hall sign suggests that the carriers are positive. Here, we extend Hall measurements up to 400 K and observe that the Hall coefficient changes back to the correct (negative) sign at about 305 K. We interpret the anomalous sign of the Hall coefficient in the context of skew scattering arising from the strong correlations between the $f$ and $d$ electrons. At energy scales where the gap is closed, the number of $d$ electrons in resonance with the $f$ electrons at the Fermi energy varies. When a large proportion of $d$ and $f$ electrons are in resonance, skew scattering is dominant, leading to the observation of the positive sign, but when fewer are in resonance, conventional scattering mechanisms dominate instead.