Strain-stabilized altermagnetism and conductivity anisotropy in FeSb2

Abstract

We show that FeSb2 experiences a transition from a conventional antiferromagnet to an altermagnet when tensile strain is applied. In the altermagnetic phase, the lifted Kramers degeneracy results in spin splitting up to ~0.2eV near the Fermi level even without spin-orbit coupling. The transition to the altermagnetic phase is accompanied by a dramatic change in the Fermi-surface geometry, which leads to a uniaxial conductivity anisotropy up to ~60%, much greater than those observed in typical ferromagnetic metals. Using density-functional theory and Wannier interpolated Fermi surfaces, we show that this magnetotransport behavior may function as an experimental indicator of the transition to the altermagnetic phase. These findings highlight FeSb2 as a versatile, strain-tunable platform for exploring and utilizing altermagnetic transport phenomena for spintronic devices.