Garg Arti, Krishnamurthy H R, Randeria Mohit
Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064, India.
Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560 012, India and JNCASR, Jakkur, Bangalore 560 064, India.
Phys Rev Lett. 2014 Mar 14;112(10):106406. doi: 10.1103/PhysRevLett.112.106406. Epub 2014 Mar 12.
We demonstrate in a simple model the surprising result that turning on an on-site Coulomb interaction U in a doped band insulator leads to the formation of a half-metallic state. In the undoped system, we show that increasing U leads to a first order transition at a finite value UAF between a paramagnetic band insulator and an antiferomagnetic Mott insulator. Upon doping, the system exhibits half-metallic ferrimagnetism over a wide range of doping and interaction strengths on either side of UAF. Our results, based on dynamical mean field theory, suggest a new route to half metallicity, and will hopefully motivate searches for new materials for spintronics.
在掺杂的带绝缘体中开启在位库仑相互作用U会导致半金属态的形成。在未掺杂的系统中，我们表明，增加U会导致在有限值UAF处发生一级相变，从顺磁带绝缘体转变为反铁磁莫特绝缘体。掺杂后，该系统在UAF两侧的广泛掺杂和相互作用强度范围内呈现半金属亚铁磁性。我们基于动态平均场理论的结果，提出了一条通往半金属性的新途径，并有望推动对自旋电子学新材料的探索。
