Speaker
Description
The discovery of altermagnetism has introduced a new class of collinear antiferromagnets that simultaneously exhibit zero net magnetization and a large, momentum-dependent spin splitting of electronic bands from crystal and spin-group symmetries. This non-relativistic splitting, distinct from ferromagnets and conventional antiferromagnets, enables spin-transport phenomena without stray magnetic fields. Among known altermagnets, CrSb is especially attractive due to its large exchange-driven spin splitting near the Fermi level and high Néel temperature, making it a promising candidate for room-temperature spintronic and topological applications.
Topological insulators such as (Bi,Sb)2Te3 host Dirac surface states with spin–momentum locking protected by time-reversal symmetry. Bringing these materials together raises important questions about the fate of topological surface states when interfaced with a magnetic system that breaks time-reversal symmetry while maintaining zero net magnetization. We present a first-principles density functional theory study of the CrSb/(Bi,Sb)2Te3 heterointerface, aimed at understanding the interplay between altermagnetic order and topological states.
Our study focuses on symmetry reduction, electronic hybridization, and spin texture at the interface, emphasizing on how the momentum-dependent spin splitting of CrSb couples to the Dirac surface states of (Bi,Sb)2Te3 through proximity effects. Unlike ferromagnetic heterostructure, the altermagnetic CrSb/(Bi,Sb)2Te3 interface provides a platform to explore magnetic–topological coupling without macroscopic magnetization, offering a route toward symmetry-controlled and spin-polarized interface states.
This work lays the theoretical groundwork for altermagnet–topological insulator heterostructures and highlights their potential for realizing novel spin–topology phenomena relevant to antiferromagnetic spintronics, topological transport, and interface-engineered quantum states.
The research was support by Canada Research Chairs (CRC) Program, NSERC Discovery Grant RGPIN-2024-06497, ARO Grant Number W911NF-25-1-0215, Canada Foundation for Innovation (CFI), Ontario Research Fund (ORF), Compute Ontario and Digital Research Alliance of Canada.
| Keyword-1 | Altermagnetism |
|---|---|
| Keyword-2 | Topological insulators |
| Keyword-3 | First-principles calculations |