报告题目: |
Spin Chern Pumping Effect in Topological Insulators |
报告人: |
Prof. Li Sheng （盛利） |
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Nanjing University
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报告时间: |
2014-04-18 15:15 |
报告地点: |
Conference Hall 322, Science Building, Tsinghua University |
主办单位: |
高等研究院 |
简介: |
Topological insulators (TIs) are a new quantum state of matter discovered recently, which are
characterized by unconventional bulk topological invariants: either the Z2 index or spin Chern
numbers. Unlike the first Chern number underlying the quantum Hall effect, up to now these
topological invariants have not been directly measurable. Here we report the theoretical discovery
of the spin Chern pumping effect, in a two-dimensional TI electrically modulated in adiabatic
cycles. In each cycle an amount of spin proportional to the sample width can be pumped into a
nonmagnetic electrode, driven by nonzero spin Chern numbers C±. Especially, by using a halfmetallic electrode, universal quantized charge pumping conductivities −C±e2/h can be measured. This discovery paves the way for direct experimental study and utilization of the robust topological properties of the TIs. |
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