Topological phase transition induced by magnetic proximity effect in two dimensions

• Published in: arXiv.org
• Main Authors: Zeng, Yijie, Wang, Luyang, Li, Song, He, Chunshan, Zhong, Dingyong, Dao-Xin Yao
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 18.06.2019
• Subjects: Antiferromagnetism; Brillouin zones; Cones; Ferromagnetism; First principles; Phase transitions; Physics - Materials Science; Physics - Mesoscale and Nanoscale Physics; Proximity; Proximity effect (electricity); Spin-orbit interactions; Topological insulators
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1906.07507

We study the magnetic proximity effect on a two-dimensional topological insulator in a CrI\(_3\)/SnI\(_3\)/CrI\(_3\) trilayer structure. From first-principles calculations, the BiI\(_3\)-type SnI\(_3\) monolayer without spin-orbit coupling has Dirac cones at the corners of the hexagonal Brillouin zone. With spin-orbit coupling turned on, it becomes a topological insulator, as revealed by a non-vanishing \(Z_2\) invariant and an effective model from symmetry considerations. Without spin-orbit coupling, the Dirac points are protected if the CrI\(_3\) layers are stacked ferromagnetically, and are gapped if the CrI\(_3\) layers are stacked antiferromagnetically, which can be explained by the irreducible representations of the magnetic space groups \(C_{3i}^1\) and \(C_{3i}^1(C_3^1)\), corresponding to ferromagnetic and antiferromagnetic stacking, respectively. By analyzing the effective model including the perturbations, we find that the competition between the magnetic proximity effect and spin-orbit coupling leads to a topological phase transition between a trivial insulator and a topological insulator.