TY - JOUR
T1 - Multi-Weyl topological semimetals stabilized by point group symmetry
AU - Fang, Chen
AU - Gilbert, Matthew J.
AU - Dai, Xi
AU - Bernevig, B. Andrei
PY - 2012/6/27
Y1 - 2012/6/27
N2 - We perform a complete classification of two-band k•p theories at band crossing points in 3D semimetals with n-fold rotation symmetry and broken time-reversal symmetry. Using this classification, we show the existence of new 3D topological semimetals characterized by C 4,6-protected double-Weyl nodes with quadratic in-plane (along k x,y) dispersion or C 6-protected triple-Weyl nodes with cubic in-plane dispersion. We apply this theory to the 3D ferromagnet HgCr 2Se 4 and confirm it is a double-Weyl metal protected by C 4 symmetry. Furthermore, if the direction of the ferromagnetism is shifted away from the [001] axis to the [111] axis, the double-Weyl node splits into four single Weyl nodes, as dictated by the point group S 6 of that phase. Finally, we discuss experimentally relevant effects including the splitting of multi-Weyl nodes by applying a C n breaking strain and the surface Fermi arcs in these new semimetals.
AB - We perform a complete classification of two-band k•p theories at band crossing points in 3D semimetals with n-fold rotation symmetry and broken time-reversal symmetry. Using this classification, we show the existence of new 3D topological semimetals characterized by C 4,6-protected double-Weyl nodes with quadratic in-plane (along k x,y) dispersion or C 6-protected triple-Weyl nodes with cubic in-plane dispersion. We apply this theory to the 3D ferromagnet HgCr 2Se 4 and confirm it is a double-Weyl metal protected by C 4 symmetry. Furthermore, if the direction of the ferromagnetism is shifted away from the [001] axis to the [111] axis, the double-Weyl node splits into four single Weyl nodes, as dictated by the point group S 6 of that phase. Finally, we discuss experimentally relevant effects including the splitting of multi-Weyl nodes by applying a C n breaking strain and the surface Fermi arcs in these new semimetals.
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U2 - 10.1103/PhysRevLett.108.266802
DO - 10.1103/PhysRevLett.108.266802
M3 - Article
C2 - 23005002
AN - SCOPUS:84862999202
SN - 0031-9007
VL - 108
JO - Physical review letters
JF - Physical review letters
IS - 26
M1 - 266802
ER -