Electronic structures and topological properties in nickelates $Ln_{n+1}$Ni$_n$O$_{2n+2}$

Jiacheng Gao; Zhijun Wang; Chen Fang; Hongming Weng

doi:10.1093/nsr/nwaa218

paper

Electronic structures and topological properties in nickelates $L n_{n + 1}$ Ni $_{n}$ O $_{2 n + 2}$

arXiv:1909.04657 · doi:10.1093/nsr/nwaa218

Abstract

After the significant discovery of the hole-doped nickelate compound Nd $_{0.8}$ Sr $_{0.2}$ NiO $_{2}$ , an analysis of the electronic structure, orbital components, Fermi surfaces and band topology could be helpful to understand the mechanism of its superconductivity. Based on the first-principles calculations, we find that Ni $3 d_{x^{2} - y^{2}}$ states contribute the largest Fermi surface. $L n 5 d_{3 z^{2} - r^{2}}$ states form an electron pocket at $Γ$ , while $5 d_{x y}$ states form a relatively bigger electron pocket at A. These Fermi surfaces and symmetry characteristics can be reproduced by our two-band model, which consists of two elementary band representations: $B_{1 g} @1 a \oplus A_{1 g} @1 b$ . We find that there is a band inversion near A, giving rise to a pair of Dirac points along A--M below the Fermi level once including spin-orbit coupling. Furthermore, we have performed the LDA+Gutzwiller calculations to treat the strong correlation effect of Ni 3d orbitals. In particular, the bandwidth of $3 d_{x^{2} - y^{2}}$ has been renormalized largely. After the renormalization of the correlated bands, the Ni $3 d_{x y}$ states and the Dirac points become very close to the Fermi level. Thus, a hole pocket at A could be introduced by hole doping, which may be related to the observed sign change of Hall coefficient. By introducing an additional Ni $3 d_{x y}$ orbital, the hole-pocket band and the band inversion can be captured in our modified model. Besides, the nontrivial band topology in the ferromagnetic two-layer compound La $_{3}$ Ni $_{2}$ O $_{6}$ is discussed and the band inversion is associated with Ni $3 d_{x^{2} - y^{2}}$ and La $5 d_{x y}$ orbitals.

arXiv comment10 pages, 7 figures, 4 tables

Electronic structures and topological properties in nickelates $L n_{n + 1}$ Ni $_{n}$ O $_{2 n + 2}$

Abstract

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Cited by in corpus (31)

Electronic structures and topological properties in nickelates Lnn+1​Nin​O2n+2​

Abstract

References in corpus (19)

Cited by in corpus (31)

Electronic structures and topological properties in nickelates $L n_{n + 1}$ Ni $_{n}$ O $_{2 n + 2}$