Critical currents of ideal quantum Hall superfluids
Critical currents of ideal quantum Hall superfluids
复制标题
理想量子霍尔超流体的临界电流
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
U. Colorado
中科院分区：
文献类型：
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作者：
M. Abolfath;A. Macdonald;L. Texas;U. Colorado
填充因子v=1的双层电子系统中的量子霍尔制度有激子凝聚超流基态时，层间距d是小于一个临界值dc。在量子霍尔平台上，通过两个层中的一个注入和移除的电流驱动携带平行电流的无耗散边缘电流和在两个层中携带相反电流的无耗散体超电流。本文讨论了在存在和不存在对称性破缺层间杂化的情况下，有限超电流双层态的理论。微观平均场方程的解存在于所有的凝聚相缠绕率为零和足够弱的杂交强度。然而，我们发现，集体不稳定性发生时，超电流超过一个临界值，主要由直接和交换层间库仑相互作用之间的竞争。使用局部稳定性准则估计临界电流，并且当d从下面接近dc时，临界电流为（dc-d）1 / 2变化。对于大的层间杂化，我们发现，临界电流是有限的孤立子不稳定性的微观起源。
Filling factor v=1 bilayer electron systems in the quantum Hall regime have an excitonic-condensate superfluid ground state when the layer separation d is less than a critical value d c . On a quantum Hall plateau current injected and removed through one of the two layers drives a dissipationless edge current that carries parallel currents and a dissipationless bulk supercurrent that carries opposing currents in the two layers. In this paper we discuss the theory of finite supercurrent bilayer states, both in the presence and in the absence of symmetry breaking interlayer hybridization. Solutions to the microscopic mean-field equations exist at all condensate phase winding rates for zero and sufficiently weak hybridization strengths. We find, however, that collective instabilities occur when the supercurrent exceeds a critical value determined primarily by a competition between direct and exchange interlayer Coulomb interactions. The critical current is estimated using a local stability criterion and varies as (d c -d) 1 / 2 when d approaches d c from below. For large interlayer hybridization, we find that the critical current is limited by a soliton instability of microscopic origin.