Room-Temperature Ferromagnetic Topological Phase in CrO${}_2$: From Tripe Fermions to Weyl Fermions

Abstract

Ferromagnetic topological semimetals due to their band topology co-existing with intrinsic magnetization exerted important influences on early study of topological fermions. However, they have not been observed in experiments up to now. In this work, we propose that rutile CrO${}_2$, a widely used half-metallic ferromagnetic material in magnetic recording taps, exhibits unexpected ferromagnetic topological features. Using first-principles calculations and symmetry analysis, we reveal that rutile CrO${}_2$ hosts the triple nodal points in the absence of spin orbital coupling (SOC). By taking into account of SOC, each triple nodal point splits into two Weyl points, which are located on the magnetic axis with four-fold rotational symmetry. Notably, the Fermi arcs and accompanying quasiparticle interference patterns are clearly visible, which facilitate experimental observations. In addition, we find that another experimentally synthesized CrO${}_2$ in CaCl${}_2$ structure, also hosts the topologically nontrivial ferromagnetic phase. Our findings substantially advance the experimental realization of ferromagnetic topological semimetals. More importantly, room-temperature time-reversal-breaking Weyl fermions in CrO${}_2$ may result in promising applications related to the topological phenomena in industry.

5 pages, 4 figures

References in corpus (13)

• WannierTools: An open-source software package for novel topological materials
• Topological quantum chemistry
• Weyl semimetal phase in non-centrosymmetric transition metal monophosphides
• Wannier representation of Z_2 topological insulators
• Z2Pack: Numerical Implementation of Hybrid Wannier Centers for Identifying Topological Materials
• Anomalous Hall Effect in Weyl Metals
• Weyl Semimetals, Fermi Arcs and Chiral Anomalies (A Short Review)
• Classification of reflection symmetry protected topological semimetals and nodal superconductors
• Weyl semimetals from noncentrosymmetric topological insulators
• Topological Hopf and chain link semimetal states and their application to Co2MnGa (Theory and Materials Prediction)
• Topological Weyl and Node-Line Semimetals in Ferromagnetic Vanadium-Phosphorous-Oxide $\beta$-V${}_2$OPO${}_4$ Compound
• Heavy Weyl fermion state in CeRu${}_4$Sn${}_6$
• Strongly Ideal Robust Weyl Semimetals in Cubic Symmetry with Spatial-Inversion Breaking

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• Large anomalous Hall, Nernst effect and topological phases in the 3d-4d/5d based oxide double perovskites
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