Chiral Dirac-like fermion in spin-orbit-free antiferromagnetic semimetals

Liu，Pengfei1,2; Zhang，Ao1; Han，Jingzhi2; Liu，Qihang1,3,4

2022-11-08

10.1016/j.xinn.2022.100343

Innovation-The European Journal of Social Science Research   Impact Factor & Quartile

1351-1610

2666-6758

Dirac semimetal is a phase of matter whose elementary excitation is described by the relativistic Dirac equation. In the limit of zero mass, its parity-time symmetry enforces the Dirac fermion in the momentum space, which is composed of two Weyl fermions with opposite chirality, to be non-chiral. Inspired by the flavor symmetry in particle physics, we theoretically propose a massless Dirac-like equation yet linking two Weyl fields with the identical chirality by assuming SU(2) isospin symmetry, independent of the space-time rotation exchanging the two fields. Dramatically, such symmetry is hidden in certain solid-state spin-1/2 systems with negligible spin-orbit coupling, where the spin degree of freedom is decoupled with the lattice. Therefore, the existence of the corresponding quasiparticle, dubbed as flavor Weyl fermion, cannot be explained by the conventional (magnetic) space group framework. The 4-fold degenerate flavor Weyl fermion manifests linear dispersion and a Chern number of ±2, leading to a robust network of topologically protected Fermi arcs throughout the Brillouin zone. For material realization, we show that the transition-metal chalcogenide CoNbS with experimentally confirmed collinear antiferromagnetic order is ideal for flavor Weyl semimetal under the approximation of vanishing spin-orbit coupling. Our work reveals a counterpart of the flavor symmetry in magnetic electronic systems, leading to further possibilities of emergent phenomena in quantum materials.

antiferromagnet isospin symmetry spin group topological semimetal Weyl fermion

SSCI ; ESCI

English

First ; Corresponding

National Natural Science Foundation of China[11874195];Guangdong Provincial Key Laboratory Of Computational Science And Material Design[2019B030301001];National Key Research and Development Program of China[2020YFA0308900];Science, Technology and Innovation Commission of Shenzhen Municipality[ZDSYS20190902092905285];

Sociology

Sociology

WOS:000883049100007

ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD

2-s2.0-85141237564

Scopus

1.Shenzhen Institute for Quantum Science and Engineering and Department of Physics,Southern University of Science and Technology,Shenzhen,518055,China
2.School of Physics,Peking University,Beijing,100871,China
3.Guangdong Provincial Key Laboratory of Computational Science and Material Design,Southern University of Science and Technology,Shenzhen,518055,China
4.Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices,Southern University of Science and Technology,Shenzhen,518055,China

Liu，Pengfei,Zhang，Ao,Han，Jingzhi,et al. Chiral Dirac-like fermion in spin-orbit-free antiferromagnetic semimetals[J]. Innovation-The European Journal of Social Science Research,2022,3(6).

Liu，Pengfei,Zhang，Ao,Han，Jingzhi,&Liu，Qihang.(2022).Chiral Dirac-like fermion in spin-orbit-free antiferromagnetic semimetals.Innovation-The European Journal of Social Science Research,3(6).

Liu，Pengfei,et al."Chiral Dirac-like fermion in spin-orbit-free antiferromagnetic semimetals".Innovation-The European Journal of Social Science Research 3.6(2022).