Tuning the conductance of dirac fermions on the surface of a topological insulator.
Tuning the conductance of dirac fermions on the surface of a topological insulator.
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DOI：
10.1103/physrevlett.104.046403
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发表时间：
2009-08
影响因子：
8.6
通讯作者：
S. Mondal;Diptiman Sen;Krishnendu Sengupta;Ravi Shankar
中科院分区：
文献类型：
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作者：
S. Mondal;Diptiman Sen;Krishnendu Sengupta;Ravi Shankar
本文研究了费米速度为v{F}的狄拉克费米子在拓扑绝缘体表面上的输运性质。我们表明，这样的结的电导，在清洁的限制和在低温下，从振荡的变化到一个单调递减的函数d超过一个临界J。这导致可能实现的磁开关使用这些结。我们还研究了这些狄拉克费米子的电导跨越势垒的宽度d和潜在的V0在这样的铁磁条的存在下，并表明，超过临界J，电导最大值的标准从chi=eV{0}d/变量普朗克的v{F}=npi的chi=（n+1/2）pi的整数n的变化。我们指出，这些新的现象在石墨烯中没有类似物，并建议可以探测它们的实验。
We study the transport properties of the Dirac fermions with a Fermi velocity v{F} on the surface of a topological insulator across a ferromagnetic strip providing an exchange field J over a region of width d. We show that the conductance of such a junction, in the clean limit and at low temperature, changes from oscillatory to a monotonically decreasing function of d beyond a critical J. This leads to the possible realization of a magnetic switch using these junctions. We also study the conductance of these Dirac fermions across a potential barrier of width d and potential V0 in the presence of such a ferromagnetic strip and show that beyond a critical J, the criteria of conductance maxima changes from chi=eV{0}d/variant Planck's over v{F}=npi to chi=(n+1/2)pi for integer n. We point out that these novel phenomena have no analogs in graphene and suggest experiments which can probe them.