摘要

Two-dimensional topological insulators (2D TIs) have been proposed as platforms for many intriguing applications, ranging from spintronics to topological quantum information processing. Realizing this potential will likely be facilitated by the discovery of new, easily manufactured materials in this class. With this goal in mind, we introduce a new framework for engineering a 2D TI by hybridizing graphene with impurity bands arising from heavy adatoms possessing large spin-orbit coupling, in particular, osmium and iridium. First-principles calculations predict that the gaps generated by this means exceed 0.2 eV over a broad range of adatom coverage; moreover, tuning of the Fermi level is not required to enter the TI state.

Furthermore, we also demonstrated that Co and Rh on graphene may produce strong quantum anomaly Hall effect, with both large perpendicular magnetic anisotropy energies and large spin-orbit coupling induced band gaps. While one spin channel has the features of TI, the other spin channel is a metal, so these systems can becharacterized  as topological half metals.

报告人简介

武汝前，1978年 2 月－1981年 1 月, 盐城师范学院物理系；1984年 8 月－ 1989年 7 月, 中国科学院物理研究所， 理学博士; 1989年 8 月－1994年 6 月, 美国西北大学物理系，Research Associate; 1994年 7 月－2001年 6 月, 美国加州州立大学Northridge校区物理系，Assistant Professor-Professor; 2001年 7 月 至今，美国加州大学Irvine校区物理系, Professor. 2013年 7 月 起兼复旦大学教授。2001年获选为美国物理学会会士。2002年起被聘为 Phys. Lett. A 在凝聚态物理方向的编辑。专长在于原创性发展和应用能带方法及计算程序，研究复杂材料的物理和化学性能。在国际上率先研究磁性薄膜及纳米磁性材料，发展了磁晶各向异性，磁光效应，磁致伸缩，磁X光二向色性计算方法。