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Research Highlight

Quantum Material Topology via Defect Engineering

Quantum Material Topology via Defect Engineering
(Top) Schematic representation of different topological phases realized by breaking specific symmetries in bulk SnTe. (Bottom left) Surface state connecting opposite Weyl nodes in Cr:SnTe shows a Fermi arc suggesting a nontrivial ferromagnetic Weyl phase (Bottom right) Berry curvature around a Weyl node carrying a topological charge.

Scientific Achievement

The topology of the quantum material, SnTe, is demonstrated to be engineered to a Weyl semimetallic or a nodal line state by controlling the type, amount, and distribution of atomic-defects.

Significance and Impact

The separation of the Weyl nodes and their energy positions are shown to be tunable with defect concentration and degree of order or disorder, allowing for the precise control of transport properties such as anomalous Hall conductivity.

Research Details

  • Thermodynamics and magnetic properties were studied to understand the defect phase diagram.
  • The topological properties were calculated within the virtual crystal approximation (to treat disorder) as well as the supercell method (to treat order).

A. Pham and P. Ganesh, "Quantum material topology via defect engineering," Phys. Rev. B 100, 241110(R) (2019).  DOI: 10.1103/PhysRevB.100.241110