New topological insulator thin film exhibits novel magnetic properties
New topological insulator thin film exhibits novel magnetic properties lead image
Researchers from Tsinghua University and Collaborative Innovation Center of Quantum Matter in Beijing, China, have successfully synthesized for the first time vanadium-doped Bi2Se3 films that exhibit ferromagnetism.
The researchers synthesized the films using molecular beam epitaxy, a method for depositing single crystal films. The vanadium doped Bi2Se3 film exhibits ferromagnetism, which is then enhanced by the decreased carrier density. The enhanced ferromagnetism indicates that quantum anomalous Hall effect may be realized in the system. A large energy gap of ∼180meV is observed at the surface states of the material, which is different from the magnetically doped (Bi,Sb)2Te3, where no surface state gap has been observed. The large energy gap suggests that the quantum anomalous Hall effect in the new material may behave differently from its predecessors.
According to co-author Ke He, this is the first time robust ferromagnetism is introduced in Bi2Se3, which is one of the most studied topological insulator materials. The discovery of a new material that probably exhibits the quantum anomalous Hall effect and dissipationless transport of electrons can be used to develop more energy efficient electronic and spintronic applications.
Source: “Ferromagnetism in vanadium-doped Bi2Se3 topological insulator films,” by Liguo Zhang, Dapeng Zhao, Yunyi Zang, Yonghao Yuan, Gaoyuan Jiang, Menghan Liao, Ding Zhang, Ke He, Xucun Ma, and Qikun Xue, APL Materials (2017). The article can be accessed at https://doi.org/10.1063/1.4990548 .
