TY - JOUR
TI - Multiple Dirac nodes and symmetry protected Dirac nodal line in orthorhombic α-RhSi
AU - Mozaffari, S.
AU - Aryal, N.
AU - Schönemann, R.
AU - Chen, K.-W.
AU - Zheng, W.
AU - McCandless, G.T.
AU - Chan, J.Y.
AU - Manousakis, E.
AU - Balicas, L.
JO - Physical Review B
PY - 2020
VL - 102
TODO - 11
SP - null
PB - American Physical Society
SN - 2469-9950, 2469-9969
TODO - 10.1103/PhysRevB.102.115131
TODO - Silicides;  Silicon;  Topology;  Transition metals, Crystalline symmetry;  De Haas-van Alphen effect;  Group representation;  Magnetic torques;  Symmetry analysis;  Topological excitations;  Topological features;  Transition metal silicides, Rhodium compounds
TODO - Exotic multifold topological excitations have been predicted and were recently observed in transition metal silicides like β-RhSi. Herein, we report that interesting topological features of RhSi are also observed in its orthorhombic α phase, which displays multiple types of Dirac nodes very close to the Fermi level ÉF. We discuss the symmetry analysis, band connectivity along high-symmetry lines using group representations, band structure, the nature of the Dirac points and of a nodal line occurring near ÉF which is protected by the crystalline symmetry. The de Haas-van Alphen effect indicates a Fermi surface in agreement with the calculations. We find an elliptically shaped nodal line very close to ÉF around and near the S point on the ky-kz plane that results from the intersection of two upside-down Dirac cones. Both Dirac points of the participating Kramers degenerate bands are only 5 meV apart; hence, an accessible magnetic field might induce a crossing between the spin-up partner of the upper Dirac cone and the spin-down partner of the lower Dirac cone, possibly explaining the anomalies observed in the magnetic torque. α-RhSi is a unique system since all bands crossing ÉF emerge from Dirac nodes. © 2020 American Physical Society.
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