Hard magnet topological semimetals in XPt3 compounds with the harmony of Berry curvature

Abstract

Topological magnetic semimetals, like Co3Sn2S2 and Co2MnGa, display exotic transport properties, such as large intrinsic anomalous (AHE) due to uncompensated Berry curvature. The highly symmetric XPt3 compounds exhibit anti-crossing gapped nodal lines, a driving mechanism in the intrinsic Berry curvature Hall effects. Uniquely, these compounds contain two sets of gapped nodal lines that harmoniously dominate the Berry curvature in this complex multi band system. We calculate a maximum AHE of 1965 S cm-1 in the CrPt3 by first principles electronic structure. We have grown high-quality CrPt3 thin films with perpendicular magnetic anisotropy by magnetron sputtering and measured a robust AHE of 1750 S cm−1 for different sputtering growth conditions. Additionally, the cubic films display an easy magnetic axis along [111] direction. The facile and scalable fabrication of these materials is prime candidates for integration into topological devices.

Crystal Defect Doping on Antiferromagnetic Topological Insulator Candidate EuMg2Bi2

“…Recently, the magnetic topological candidate EuMg 2 Bi 2 has attracted much attention in the materials community as a magnetic topological candidate strongly influenced by its characteristic trigonal La 2 O 3 -type structure, isostructural to the type-II nodal-line semimetal Mg 3 Bi 2 discovered by Chang et al − This material exhibits strong spin orbit coupling of Bi layers capable of hosting topological electronic states with alternating rare-earth layers that promote a potential interplay between the Dirac fermions and magnetism. Unlike nonmagnetic counterparts, magnetic topological materials offer a unique platform to control quantum transport properties through a topological quasiparticle and magnetic coupling. − Not only is this of fundamental interest but can be applied to a range of applications, including thermoelectric materials, photovoltaics, and quantum computation . A promising strategy to manipulate the magnetic and electrical properties of magnetic topological candidates has been realized through defect doping.…”

Observation of a linked-loop quantum state in a topological magnet

“…Such node loops are called Weyl loops, by analogy with the two-fold degeneracy of a Weyl point [16][17][18][29][30][31]. Weyl loops are extremely effective at concentrating Berry curvature, giving rise to giant anomalous Hall and Nernst effects, up to room temperature and promising for technological applications [20,[39][40][41][42][43]. In crystallographic space groups with multiple perpendicular mirror planes, different Weyl loops living in different mirror planes can naturally link each other [21,26].…”

Anomalous Hall Effect in Epitaxial Thin Films of the Hexagonal Heusler MnPtGa Noncollinear Hard Magnet

“…In this region, the Weyl Berry curvature dominates the Hall conductivity in the multiband system. [ 29 ] While there is a considerable variation in the magnitude of the AHC in a narrow energy range, the spin‐resolved DOS (not shown) remains relatively monotone. In our calculations, the AHC is found to range between −40 and −530 Ω −1 cm −1 , which constitutes a semi‐quantitative agreement with the values reported experimentally hereinafter.…”

“…AHC scaling: a materials catalogue. [ 29,36–43 ] Experimentally reported absolute values of the AHC $$|\sigma _{{\rm{xy}}}^{{\rm{AH}}}|$$ versus the corresponding σ xx , for a selection of magnetic systems whose AHE is considered to originate from the Berry curvature‐driven intrinsic mechanism. The extracted AHC of MnPtGa films (this work) displays an unusual nonmonotonic evolution with σ xx , even though well within the conductivity regime which typically corresponds to an AHE of intrinsic Berry curvature origin.…”