主讲人简介：Prof. Ching Yao Fong, Distinguished Professor, Department of Physics, University of California, USA；Chair of American Physical Society-California Section；Outstanding Referee of American Physical Society. His research interests focus on first-principles calculations based on density functional theory. The objective is to design new spintronic materials by using first principles codes. In particular, materials exhibit half metallic properties.

内容摘要：Ideal spintronic devices should be made of a half metal. One of the half Heusler alloys, NiMnSb, was the first one to be predicted to exhibit half metallic properties. However, all the latter predictions of half metals happen at lattice constants which are larger than the corresponding optimized values. This will cause short life time of the devices made of the alloys because they are strained. Furthermore, there are experimental evidences that large magnetic moments/unit-cell possessed by materials will exhibit ferromagnetism above room temperature – high Curie temperature.Based on the electronegativity and the Pauli principle, we designed a half Heulser alloy, LiCrS, exhibiting its half metallic properties at the optimized lattice constant of a metastable structure, the α-phase. It also has the largest magnetic moment formed by the 3d states.It is known that the spin-orbit effect can destroy the half metallicity. We examined the effect of the spin –orbit interaction in LiCrS and show that the effect is negligible.Finally, the issue of growth is considered because half Heulser alloys can have three different structural phases and ferro- and antiferro-magnetic states. The lattice constants of the other phases and the states may cause proximity effect to interfere the growth of the favored LiCrS. A suggestion is made to grow the α-phase LiCrS.

讲座语言：英语