TY - JOUR
T1 - Creating Weyl nodes and controlling their energy by magnetization rotation
AU - Ghimire, Madhav Prasad
AU - Facio, Jorge I.
AU - You, Jhih Shih
AU - Ye, Linda
AU - Checkelsky, Joseph G.
AU - Fang, Shiang
AU - Kaxiras, Efthimios
AU - Richter, Manuel
AU - Van Den Brink, Jeroen
N1 - Publisher Copyright:
© 2019 authors. Published by the American Physical Society.
PY - 2019/12
Y1 - 2019/12
N2 - As they do not rely on the presence of any crystal symmetry, Weyl nodes are robust topological features of an electronic structure that can occur at any momentum and energy. Acting as sinks and sources of Berry curvature, Weyl nodes have been predicted to strongly affect the transverse electronic response, like in the anomalous Hall or Nernst effects. However, to observe large anomalous effects the Weyl nodes need to be close to or at the Fermi level, which implies the band structure must be tuned by an external parameter, e.g., chemical doping. Here we show that in a ferromagnetic metal tuning of the Weyl node energy and momentum can be achieved by rotation of the magnetization. First, taking as example the elementary magnet hcp-Co, we use electronic structure calculations based on density-functional theory to show that by canting the magnetization away from the easy axis, Weyl nodes can be driven exactly to the Fermi surface. Second, we show that the same phenomenology applies to the kagome ferromagnet Co3Sn2S2, in which we additionally show how the dynamics in energy and momentum of the Weyl nodes affects the calculated anomalous Hall and Nernst conductivities. Our results highlight how the intrinsic magnetic anisotropy can be used to engineer Weyl physics.
AB - As they do not rely on the presence of any crystal symmetry, Weyl nodes are robust topological features of an electronic structure that can occur at any momentum and energy. Acting as sinks and sources of Berry curvature, Weyl nodes have been predicted to strongly affect the transverse electronic response, like in the anomalous Hall or Nernst effects. However, to observe large anomalous effects the Weyl nodes need to be close to or at the Fermi level, which implies the band structure must be tuned by an external parameter, e.g., chemical doping. Here we show that in a ferromagnetic metal tuning of the Weyl node energy and momentum can be achieved by rotation of the magnetization. First, taking as example the elementary magnet hcp-Co, we use electronic structure calculations based on density-functional theory to show that by canting the magnetization away from the easy axis, Weyl nodes can be driven exactly to the Fermi surface. Second, we show that the same phenomenology applies to the kagome ferromagnet Co3Sn2S2, in which we additionally show how the dynamics in energy and momentum of the Weyl nodes affects the calculated anomalous Hall and Nernst conductivities. Our results highlight how the intrinsic magnetic anisotropy can be used to engineer Weyl physics.
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U2 - 10.1103/PhysRevResearch.1.032044
DO - 10.1103/PhysRevResearch.1.032044
M3 - Article
AN - SCOPUS:85078269419
SN - 2643-1564
VL - 1
JO - Physical Review Research
JF - Physical Review Research
IS - 3
M1 - 032044
ER -