Altermagnetic bulk and topological surface magnetizations for CrSb single crystals

TL;DR

This paper experimentally investigates the angle-dependent magnetization and topological surface states in CrSb single crystals, revealing unique magnetic behaviors linked to altermagnetism and topological features.

Contribution

It provides the first experimental demonstration of both bulk altermagnetic and topological surface magnetizations in CrSb single crystals.

Findings

Magnetization oscillates around zero with angle, indicating alternating spin splitting.

Topological surface states contribute to diamagnetic-like negative slope in M(H).

Multiple magnetic phases influence the magnetization behavior.

Abstract

We experimentally investigate the angle dependence of magnetization $M(\alpha)$ for single crystals of CrSb. CrSb belongs to a new class of altermagnetic materials, the small net magnetization is accompanied by alternating spin splitting in the k-space. In addition, CrSb reveals also topological features with Weyl surface states originating from bulk band topology. We observe, that $M(\alpha)$ oscillates around zero value, so magnetization is positive for $M(\alpha)$ maxima and it is negative for $M(\alpha)$ minima. The magnetization reversal curves $M(H)$ are non-linear with low-field hysteresis, but with almost linear high-field branches. The slope of the linear branches well correlates with $M(\alpha)$ oscillations, so it is positive for $M(\alpha)$ maxima and negative for $M(\alpha)$ minima. We demonstrate, that the interplay between the positive and the negative $M(H)$ slopes originates from several magnetic phases in CrSb. In particular, current-carrying topological surface states are responsible for the diamagnetic-like $M(H)$ negative slope, which dominates for the directions of full spin compensation in the bulk CrSb altermagnetic spectrum. Due to the spin-momentum locking, topological surface states are spin-polarized, which is responsible for the low-field hysteresis. Thus, we experimentally demonstrate both the altermagnetic bulk and the topological surface magnetizations for the altermagnetic candidate CrSb.