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学术报告:Polarized spin and valley transport across ferromagnetic barriers in silicene, integer and half-integer quantum Hall effect

报告题目:Polarized spin and valley transport across ferromagnetic barriers

in silicene, integer and half-integer quantum Hall effect

报 告 人: P.Vasilopoulos教授 (加拿大Concordia大学)

报告地点: 致远楼213

报告时间:20171122日星期三 下午4:00

摘要:

(a) We study ballistic electron transport through silicene barriers, of height U, in the presence of an exchange field M and a normal electric field Ez. Away from the Dirac point (DP), the spin- and valley-resolved conductances, as functions of U, exhibit resonances while close to it there is a pronounced dip that can be trans-formed into a transport gap by varying Ez. The spin polarization near the DP increases with Ez or M and becomes nearly perfect above certain Ez or M values.          

(b) The low-energy physics of silicene is described by Dirac electrons with a strong spin-orbit interaction and its band structure can be controlled by an external electric field Ez. We study magnetotransport in the presence of a perpendicular magnetic field B. For finite Ez the spin and valley degeneracy of the Landau levels (LLs) is lifted and leads to additional Hall conductivity plateaux, at half-integral values of 4e^2/h, due to spin intra-LL transitions, that are 1) absent in graphene and 2) more sensitive to disorder and thermal broadening than the main ones, that occur at integral values of 4e^2/h, when the Fermi level passes through the LLs. The results are critically contrasted with those for graphene on a substrate.

个人简介:Dr. P. Vasilopoulos 现为加拿大蒙特利尔Concordia大学物理学教授。1972年本科毕业于希腊Thessaloniki大学,1979年于加拿大Concordia大学获硕士学位,1982年于蒙特利尔大学获博士学位。1982-1984年于德国斯图加特马普所及1984-1987年于蒙特利尔大学做博士后。

1987-1990年于蒙特利尔工业大学及1991-1992年于Concordia大学任职研究员。1992-1999年为Concordia大学副教授,1999年至今为Concordia大学教授。Vasilopoulos教授长期从事半导体微纳结构电子输运理论研究。

现已在PRLNano LettersAPL, PRB 等期刊发表学术论文230多篇。论文被引用5500多次,H因子38


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