## arXiv Analytics

### arXiv:1909.04657 [cond-mat.mtrl-sci]AbstractReferencesReviewsResources

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

Published 2019-09-10Version 1

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 $3d_{x^2-y^2}$ states contribute the largest Fermi surface. $Ln~5d_{3z^2-r^2}$ states form an electron pocket at $\Gamma$, while $5d_ {xy}$ states form a relatively bigger pocket at A. These Fermi surfaces and symmetries can be reproduced by our two-band model, which consists of two elementary band representations: $B_{1g}@1a~\oplus~A_{1g}@1b$. By hole doping, a hole pocket originating from Ni $3d_{xy}$ orbital can be introduced, which may be related to the observed sign change of Hall coefficient. We find that there is a band inversion happened at A, which can be affected by the value of Coulomb interaction $U$ in the calculations. With small $U$ and spin-orbital coupling, it gives rise to a pair of Dirac points along A-M. By introducing an additional Ni $3d_{xy}$ orbital, the hole-pocket band and the possible band inversion can be captured in the 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 $3d_{x^2-y^2}$ and La $5d_{xy}$ orbitals.

Comments: 10 pages, 7 figures, 4 tables
Related articles: Most relevant | Search more
arXiv:cond-mat/0312245 (Published 2003-12-10)
Electronic structure of wurtzite and zinc-blende AlN
arXiv:0710.4841 [cond-mat.mtrl-sci] (Published 2007-10-25)
Electronic structure of the c(4 x 2) reconstructed Ge(001) surface
arXiv:0910.5811 [cond-mat.mtrl-sci] (Published 2009-10-30, updated 2010-03-25)
Electronic structure of turbostratic graphene