Bibliographic Details
| Title: |
Lattice distortion effects on topological phases in (LaNiO$_3$)$_2$/(LaAlO$_3$)$_N$ heterostructures grown along the [111] direction |
| Authors: |
Rüegg, Andreas, Mitra, Chandrima, Demkov, Alexander A., Fiete, Gregory A. |
| Source: |
Phys. Rev. B 88, 115146 (2013) |
| Publication Year: |
2013 |
| Collection: |
Condensed Matter |
| Subject Terms: |
Condensed Matter - Strongly Correlated Electrons |
| More Details: |
We theoretically investigate the influence of internal and external strain on topological phases in (LaNiO$_3$)$_2$/(LaAlO$_3$)$_N$ heterostructures grown along the [111] direction. At the Hartree-Fock level, topological phases originate from an interaction-generated effective spin-orbit coupling that opens a gap in the band structure. For the unstrained system, there is a quadratic band touching at the $\Gamma$ point at the Fermi energy for unpolarized electrons and Dirac points at K, K$'$ at the Fermi energy for fully polarized electrons. Using density functional theory we show that the quadratic band touching and Dirac points are remarkably stable to internal strain-induced out-of-plane distortions and rotations of the oxygen octahedra, which we compute. The lack of a gap opening from internal strain implies a robustness to the mean-field predicted topological phases for both the polarized and unpolarized systems. We also consider an external strain imposed along the [001] cubic direction and show this can open a gap at the $\Gamma$ point but leaves the Dirac points intact. Finally, we compute a phase diagram for parameters relevant to LaNiO$_3$ which shows that strain favors a phase with polarized orbitals and antiferromagnetic spin order, but leaves earlier predictions for a zero-magnetic field topological quantum Hall state essentially unchanged. Taken together, our results suggest that the [111] growth direction in perovskites may lead to thin films that are relatively immune to distortion effects compared to those grown along [001].
Comment: 10 pages, 9 figures; published version |
| Document Type: |
Working Paper |
| DOI: |
10.1103/PhysRevB.88.115146 |
| Access URL: |
http://arxiv.org/abs/1306.1002 |
| Accession Number: |
edsarx.1306.1002 |
| Database: |
arXiv |
