Details

Autor(en) / Beteiligte

• Chen, Cong
• Song, Zhida
• Zhao, Jian-Zhou
• Chen, Ziyu
• Yu, Zhi-Ming
• Sheng, Xian-Lei
• Yang, Shengyuan A.

Titel

Universal Approach to Magnetic Second-Order Topological Insulator

Ist Teil von

• Physical review letters, 2020-07, Vol.125 (5), p.1-056402, Article 056402

Ort / Verlag

College Park: American Physical Society

Erscheinungsjahr

2020

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• We propose a universal practical approach to realize magnetic second-order topological insulator (SOTI) materials, based on properly breaking the time reversal symmetry in conventional (first-order) topological insulators. The approach works for both three dimensions (3D) and two dimensions (2D), and is particularly suitable for 2D, where it can be achieved by coupling a quantum spin Hall insulator with a magnetic substrate. Using first-principles calculations, we predict bismuthene on EuO(111) surface as the first realistic system for a two-dimensional magnetic SOTI. We explicitly demonstrate the existence of the protected corner states. Benefitting from the large spin-orbit coupling and sizable magnetic proximity effect, these corner states are located in a boundary gap ∼ 83     meV , and hence can be readily probed in experiment. By controlling the magnetic phase transition, a topological phase transition between a first-order TI and a SOTI can be simultaneously achieved in the system. The effect of symmetry breaking, the connection with filling anomaly, and the experimental detection are discussed.