Nontrivial Berry phase in magnetic BaMnSb2 semimetal

Abstract

The subject of topological materials has attracted immense attention in condensed-matter physics, because they host new quantum states of matter containing Dirac, Majorana, or Weyl fermions. Although Majorana fermions can only exist on the surface of topological superconductors, Dirac and Weyl fermions can be realized in both 2D and 3D materials. The latter are semimetals with Dirac/Weyl cones either not tilted (type I) or tilted (type II). Although both Dirac and Weyl fermions have massless nature with the nontrivial Berry phase, the formation of Weyl fermions in 3D semimetals require either time-reversal or inversion symmetry breaking to lift degeneracy at Dirac points. Here, we demonstrate experimentally that canted antiferromagnetic BaMnSb2 is a 3D Weyl semimetal with a 2D electronic structure. The Shubnikov-de Hass oscillations of the magnetoresistance give nearly zero effective mass with high mobility and the nontrivial Berry phase. The ordered magnetic arrangement (ferromagnetic ordering in the ab plane and antiferromagnetic ordering along the c axis below 286 K) breaks the time-reversal symmetry, thus offering us an ideal platform to study magnetic Weyl fermions in a centrosymmetric material.

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Cited by in corpus (16)

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• Fermions and bosons in nonsymmorphic PdSb2 with sixfold degeneracy
• Crystal growth, microstructure and physical properties of SrMnSb${}_2$
• Magnetic order induces symmetry breaking in the single crystalline orthorhombic CuMnAs semimetal
• Dirac Fermions and Possible Weak Antilocalization in LaCuSb${}_2$
• Anisotropic Berry phase in the Dirac nodal-line semimetal ZrSiS: The effect of spin-orbit coupling
• Magnetic and electronic structure of the topological semimetal YbMnSb${}_2$
• Spin dynamics of a magnetic Weyl semimetal Sr${}_{1-x}$Mn${}_{1-y}$Sb${}_2$
• High-field Studies on Layered Magnetic and Polar Dirac Metals
• Coexistence of Dirac fermion and charge density wave in square-net-based semimetal LaAuSb2
• Unusual Electronic Structure of Dirac Material BaMnSb${}_2$ Revealed by Angle-Resolved Photoemission Spectroscopy
• Molecular beam deposition of a new layered pnictide with distorted Sb square nets
• C-type antiferromagnetic structure of topological semimetal CaMnSb${}_2$
• Field-induced metal-to-insulator transition and colossal anisotropic magnetoresistance in a nearly Dirac material EuMnSb${}_2$