AHMF & Cadet Program Joint Seminarのご案内
AHMF & Cadet Program Joint Seminar
講師 (Speaker): Dr. Judit Romhányi
沖縄科学技術大学院大学(Okinawa Institute of Science and Technology Graduate
日時 (Date & Time): １２月８日 午後４時２０分~ (16:20-, December 8)
場所 (Venue): 極限科学棟二階会議室 (KYOKUGEN building, 2F meeting room)
タイトル(Title) : Spin-Orbit Dimers and Non-Collinear Phases in d1 Cubic Double Perovskites
Heavy transition metal compounds have recently attracted much interest in the community. In them physical properties are strongly influenced by spin-orbit coupling. We formulate and study a microscopic spin-orbital model for a family of cubic double perovskites with d1 ions occupying frustrated fcc sublattice.
We perform variational approach and a complimentary analytical analysis that reveal a rich variety of phases emerging from the interplay of Hund’s coupling and spin-orbit interaction. The phase diagram contains non-collinear ordered states, with or without net moments, and, remarkably, a large window of magnetically disordered spin-orbit dimer phase.
We discuss the physical origin of the unusual amorphous valence bond state experimentally suggested for Ba2BMoO6 (B=Y,Lu), and predict possible ordered patterns in Ba2BOsO6 (B=Na,Li) compounds. We provide a theoretical background for all available experimental observation in these materials.
The proposed physical picture applies to a broader family of heavy transition metal compounds. Furthermore, our work can help understand magnetism in spin-orbit assisted Mott insulators, and illustrate how frustration may emerge on the account of orbital physics.
 Judit Romhányi, Leon Balents and George Jackeli, arXiv:1611.00646 (submitted to PRL)
Masayuki Hagiwara (Center for Advanced High Magnetic Field Science)