文献类型：期刊文献

英文题名：Strain-induced half-valley metals and topological phase transitions in MBr2 monolayers (M = Ru, Os)

作者：Huan, Hao[1,2,3];Xue, Yang[1,2,3,4];Zhao, Bao[1,2,3,5];Gao, Guanyi[1,2,3];Bao, Hairui[1,2,3];Yang, Zhongqin[1,2,3,6]

机构：[1]Fudan Univ, State Key Lab Surface Phys, Shanghai 200433, Peoples R China;[2]Fudan Univ, Key Lab Computat Phys Sci, MOE, Shanghai 200433, Peoples R China;[3]Fudan Univ, Dept Phys, Shanghai 200433, Peoples R China;[4]East China Univ Sci & Technol, Sch Sci, Shanghai 200237, Peoples R China;[5]Liaocheng Univ, Sch Phys Sci & Informat Technol, Shandong Key Lab Opt Commun Sci & Technol, Liaocheng 252059, Shandong, Peoples R China;[6]Shanghai Qi Zhi Inst, Shanghai 200030, Peoples R China

年份：2021

卷号：104

期号：16

外文期刊名：PHYSICAL REVIEW B

收录：;EI(收录号：20214611144743);WOS:【SCI-EXPANDED(收录号:WOS:000713115900005)】；

基金：The authors are grateful to Prof. Yuanbo Zhang for very helpful discussion. This work was supported by National Natural Science Foundation of China under Grants No. 11574051, No. 11874117, No. 11604134, No. 11904101, and No. 12174059 and Natural Science Foundation of Shang-hai under Grant No. 21ZR140820. The calculations were performed at the High Performance Computational Center (HPCC) of the Department of Physics at Fudan University.

语种：英文

外文关键词：Metals - Calculations - Degrees of freedom (mechanics) - Landforms - Microelectronics - Polarization

摘要：The target of valleytronics developments is to manipulate the valley degree of freedom and utilize it in microelectronics as charge and spin degrees of freedom. Based on first-principles calculations, we demonstrate that MBr2 (M = Ru, Os) monolayers are intrinsically ferrovalley materials with large valley polarization up to 530 meV. Compressive strain can induce phase transitions in the materials from ferrovalley insulators to complete valley-polarized metals, called half-valley metals, in analogy to the concept of half metals in spintronics. With the increase of the strain, the materials become Chern insulators, whose edge states are chiral-spin-valley locking. The phase transition is caused by sequent band inversions of the dxy/dx2-y2 and dz2 orbitals at K- and K+ valleys, analyzed based on a strained k center dot p model. Our work provides a pathway for carrying out low-dissipation electronics devices with complete spin and valley polarizations.