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arXiv 1111.5273cond-mat.mes-hall
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密度调制量子线和量子环中的定域端态

Localized end states in density modulated quantum wires and rings

Suhas Gangadharaiah, Luka Trifunovic, Daniel Loss

摘要:

我们研究了存在由化学势的周期性调制引起的电荷密度波隙的有限量子线和量子环。我们表明,出现在电线的两端的Tamm-Shockley束缚态是稳定的,对弱无序和相互作用,离散开链和连续系统。低能物理可以映射到描述大质量狄拉克费米子和束缚态的Jackiw-Rebbi方程。我们通过连续模型处理相互作用,并表明它们增加了电荷间隙,并进一步本地化的最终状态。在具有弱连接的Aharonov-Bohm环中,束缚态引起了谱和持续电流随外通量变化的不寻常的$4π$周期性.置于线的相对端上的两个局域态中的电子可以经由交换相互作用而相互作用,并且这种设置可以用作托管自旋量子位的双量子点。

英文摘要:

We study finite quantum wires and rings in the presence of a charge density wave gap induced by a periodic modulation of the chemical potential. We show that the Tamm-Shockley bound states emerging at the ends of the wire are stable against weak disorder and interactions, for discrete open chains and for continuum systems. The low-energy physics can be mapped onto the Jackiw-Rebbi equations describing massive Dirac fermions and bound end states. We treat interactions via the continuum model and show that they increase the charge gap and further localize the end states. In an Aharonov-Bohm ring with weak link, the bound states give rise to an unusual $4π$-peridodicity in the spectrum and persistent current as function of an external flux. The electrons placed in the two localized states on the opposite ends of the wire can interact via exchange interactions and this setup can be used as a double quantum dot hosting spin-qubits.

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