Stanene on a SiC(0001) surface: a candidate for realizing quantum anomalous Hall effect

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Materials

Background:

• Stanene, analogous to graphene, possesses p_z-orbital Dirac states.
• Growth on substrates often disrupts these intrinsic states due to strong interfacial interactions.

Purpose of the Study:

• Investigate topological states in stanene on 4H-SiC(0001).
• Determine the orbital origin of these states and their robustness against interfacial effects.
• Explore the potential for realizing the quantum anomalous Hall effect.

Main Methods:

• First-principles calculations.
• Analysis of electronic band structure and orbital contributions.
• Berry curvature and edge state calculations.
• Effective model construction.

Main Results:

• Quadratic topological states derived from p_x,y orbitals were identified in stanene on 4H-SiC(0001).
• These p_x,y-orbital states remain intact despite strong interfacial interactions.
• An observable band gap of 22.97 meV was induced by spin-orbital coupling and an exchange field.
• Topological phase with Chern number C = 2 was confirmed, indicating potential for quantum anomalous Hall effect.

Conclusions:

• Stanene on 4H-SiC(0001) hosts robust topological states originating from p_x,y orbitals, unaffected by substrate interactions.
• The observed band gap and topological properties suggest potential for near-room-temperature quantum anomalous Hall effect.
• The findings offer a pathway for designing other two-dimensional topological materials.