Researchers from Oak Ridge National Laboratory (ORNL) have proposed a mechanism to control the magnetic properties of topological quantum material (TQM) by using magnetoelectric coupling: a mechanism that uses a heterostructure of TQM with two-dimensional (2D) ferroelectric material, which can dynamically control the magnetic order by changing the polarization of the ferroelectric material and induce possible topological phase transitions.
The novel concept was demonstrated using the example of the bilayer MnBi2Te4 on ferroelectric In2Se3 or In2Te3, where the polarization direction of the 2D ferroelectrics determines the interfacial band alignment and consequently the direction of the charge transfer. This charge transfer, in turn, enhances the stability of the ferromagnetic state of MnBi2Te4 and leads to a possible topological phase transition between the quantum anomalous Hall (QAH) effect and the zero plateau QAH.
Discovered in the 1980s, a topological material is a new phase of material whose discoverers received a Nobel Prize in 2016. Using only an electric field, the ORNL researchers transformed a normal insulator into a magnetic topological insulator. This material allows electricity to flow across its surface and edges with no energy dissipation. The electric field induces a change in the state of matter.
The team's work could provide a route to dynamically alter the magnetic ordering of TQMs and could lead to the discovery of new multifunctional topological heterostructures. “The research could result in many practical applications, such as next-generation electronics, spintronics and quantum computing,” said ORNL’s Mina Yoon, who led the study.