Press Releases

2021.07.09

Ferromagnetism and giant magnetoresistance in zinc-blende FeAs monolayers embedded in semiconductor structures : Assistant Professor Le Duc Anh, Institute of Engineering Innovation, Taiki Hayakawa(M2 : at the time), Department of Electrical Engineering and Information Systems, Yuji Nakagawa(D3 : at the time), Department of Applied Physics, Associate Professor Masaki Kobayashi, Project Researcher Yoshihiro Yoshida, Center for spintronics Research Network, Professor Yoshihiro Iwasa, Professor Masaaki Tanaka, Department of Applied Physics, and other researchers.

Material structures containing tetrahedral FeAs bonds, depending on their density and geometrical distribution, can host several competing quantum ground states ranging from superconductivity to ferromagnetism. Here we examine structures of quasi two-dimensional (2D) layers of tetrahedral Fe-As bonds embedded with a regular interval in a semiconductor InAs matrix, which resembles the crystal structure of Fe-based superconductors. Contrary to the case of Fe-based pnictides, these FeAs/InAs superlattices (SLs) exhibit ferromagnetism, whose Curie temperature (TC) increases rapidly with decreasing the InAs interval thickness tInAs (TC  tInAs−3), and an extremely large magnetoresistance up to 500% that is tunable by a gate voltage. Our first principles calculations reveal the important role of disordered positions of Fe atoms in the establishment of ferromagnetism in these quasi-2D FeAs-based SLs. These unique features mark the FeAs/InAs SLs as promising structures for spintronic applications.



Nature Communications : https://www.nature.com/articles/s41467-021-24190-w