Direction-Dependent Conduction Polarity in Altermagnetic CrSb

TL;DR

This study reports the experimental observation of direction-dependent conduction polarity in altermagnetic CrSb, revealing a multicarrier conduction mechanism that varies with crystallographic direction and can be tuned by doping.

Contribution

It provides the first experimental evidence of direction-dependent conduction polarity in CrSb and links it to a multicarrier mechanism predicted by DFT calculations.

Findings

Conduction is hole-dominated along the c-axis and electron-dominated in the ab-plane.

DDCP is sensitive to doping and can be suppressed by hole doping.

DFT predicts DDCP occurs near the Fermi level and is tunable.

Abstract

CrSb has recently gained immense attention as an altermagnetic candidate. This work reports on the experimental observation of direction-dependent conduction polarity (DDCP) in altermagnetic CrSb through Hall and Seebeck thermopower measurements. Conduction is dominated by holes along the c-axis and by electrons in the ab-plane of the hexagonal crystal of CrSb. Density functional theory (DFT) calculations indicate that DDCP in CrSb arises from a multicarrier mechanism, where electrons and holes living in distinct bands dominate conduction along different crystallographic directions. Furthermore, DFT predicts that DDCP exists within a narrow energy window near the Fermi level and is sensitive to small doping levels. This prediction is experimentally validated by the loss of DDCP in hole-doped Cr$_{0.98}$V$_{0.02}$Sb. These findings highlight the potential for tunable electronic behavior in CrSb, offering promising avenues for applications in devices that require both p-type and n-type functionalities within a single material.