Electronic band structure and surface states in Dirac semimetal LaAgSb${}_2$

Abstract

LaAgSb${}_2$ is a Dirac semimetal showing charge density wave (CDW) order. Previous ARPES results suggest the existence of the Dirac-cone-like structure in the vicinity of the Fermi level along the $\Gamma$-M direction [X. Shi et al., Phys. Rev. B 93, 081105(R) (2016)]. This paper is devoted to a complex analysis of the electronic band structure of LaAgSb${}_2$ by means of angle-resolved photoemission spectroscopy (ARPES) and theoretical calculations within the direct ab initio method as well as tight binding model formulation. To investigate the possible surface states we performed the direct DFT slab calculation and the surface Green function calculation for the (001) surface. The appearance of the surface states, which depends strongly on surface, points to the conclusion that LaSb termination is realized in the cleaved crystals. Moreover, the surface states predicted by our calculations at the $\Gamma$ and $X$ points are found by ARPES. Nodal lines, which exist along X--R and M-A path due to crystal symmetry, are also observed experimentally. The calculations reveal another nodal lines, which originate from vanishing of spin-orbit coupling and are located at X-M-A-R plane at the Brillouin zone boundary. In addition, we analyze band structure along the $\Gamma$-M path to verify, whether Dirac surface states can be expected. Their appearance in this region is not confirmed.

14 pages, 12 figures, Supplemental Material (4 pages, 5 figures)

References in corpus (14)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• A precise method for visualizing dispersive features in image plots
• Unexpected Dirac-Node Arc in the Topological Line-Node Semimetal HfSiS
• Dirac Line-nodes and Effect of Spin-orbit Coupling in Non-symmorphic Critical Semimetal MSiS (M=Hf, Zr)
• Non-symmorphic band degeneracy at the Fermi level in ZrSiTe
• Observation of two-dimensional Fermi surface and Dirac dispersion in YbMnSb${}_2$
• Revealing extremely low energy amplitude modes in the charge-density-wave compound LaAgSb${}_2$
• Observation of multiple nodal-lines in SmSbTe
• Dirac Fermions and Possible Weak Antilocalization in LaCuSb${}_2$
• Hydrostatic pressure study of pure and doped La1-xRxAgSb2 (R = Ce, Nd) charge-density-wave compounds
• Weyl-like points from band inversions of spin-polarised surface states in NbGeSb
• Evidence for nesting driven charge density waves instabilities in a quasi-two-dimensional material: LaAgSb2
• Successive destruction of charge density wave states by pressure in LaAgSb${}_2$
• Magnetotransport studies of the Sb square-net compound LaAgSb${}_2$ under high pressure and rotating magnetic fields

Cited by in corpus (5)

• Coexistence of Dirac fermion and charge density wave in square-net-based semimetal LaAuSb2
• Emergent impervious band crossing in the bulk in topological nodal line semimetal ZrAs${}_2$
• Correlation stabilized ferromagnetic MnRuAs with distorted kagome lattice
• Tight-binding model with sublattice-asymmetric spin-orbit coupling for square-net nodal line Dirac semimetals
• Dirac Dispersions and Fermi Surface Nesting in LaCuSb${}_2$