Unusual Shubnikov-de Haas oscillations in BiTeCl

TL;DR

This study investigates Shubnikov-de Haas oscillations in BiTeCl, revealing two distinct frequencies linked to Rashba spin-split Fermi surfaces, with unexpected rapid suppression of one oscillation at low temperatures.

Contribution

First detailed measurement of SdH oscillations in BiTeCl identifying two Fermi surfaces and their properties, highlighting unusual temperature dependence of the outer Fermi sheet.

Findings

Two distinct SdH frequencies corresponding to inner and outer Fermi sheets.

Rapid suppression of the outer Fermi sheet oscillation above 4 K.

Identification of Rashba spin-split bulk conduction bands.

Abstract

We report measurements of Shubnikov-de Haas (SdH) oscillations in single crystals of BiTeCl at magnetic fields up to 31 T and at temperatures as low as 0.4 K. Two oscillation frequencies were resolved at the lowest temperatures, $F_{1}=65 \pm 4$ Tesla and $F_{2}=156 \pm 5$ Tesla. We also measured the infrared optical reflectance $\left(\cal R(\omega)\right)$ and Hall effect; we propose that the two frequencies correspond respectively to the inner and outer Fermi sheets of the Rashba spin-split bulk conduction band. The bulk carrier concentration was $n_{e}\approx1\times10^{19}$ cm$^{-3}$ and the effective masses $m_{1}^{*}=0.20 m_{0}$ for the inner and $m_{2}^{*}=0.27 m_{0}$ for the outer sheet. Surprisingly, despite its low effective mass, we found that the amplitude of $F_{2}$ is very rapidly suppressed with increasing temperature, being almost undetectable above $T\approx4$ K.