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arXiv 2202.00029cond-mat.mes-hall
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Luttinger液体接近超导体时隧道密度态的隧道密度态:非局域相互作用的影响

Tunneling density of states in Luttinger Liquid in proximity to a superconductor: Effect of non-local interaction

Indian Institute of Science Education and Research (IISER) Kolkata(印度科学教育研究所加尔各答分校)

Amulya Ratnakar, Sourin Das

AI总结:

研究非局域相互作用与超导相关性在Luttinger液体接近超导体接合处对隧道密度态的影响,揭示非局域相互作用如何增强超导相关性引起的隧道密度态增强。

摘要:

最近的研究表明,在仅由非局域密度-密度相互作用驱动的Luttinger液体(LL)中,隧道密度态(TDOS)可能出现增强,而非预期的抑制。此外,已知在接近超导体(SC)的LL在零能极限附近会增强TDOS。本文研究了非局域密度-密度相互作用与超导相关性在SC-LL接合处TDOS中的相互作用,其中LL可能在整数或分数量子Hall态的边缘实现。我们展示在适当选择非局域相互作用参数的情况下,LL量子线(QW)由于接合处的超导相关性引起的TDOS增强可以进一步放大,这通过弱相互作用极限下的简洁代数表达式得到证明。我们还展示,在包含本地和非局域相互作用的完整参数范围内,LL接合处具有“超导”边界条件和“非超导电荷守恒”边界条件(在Phys. Rev. B 104, 045402 (2021)中讨论)的增强TDOS区域是互斥的。我们展示这一事实可以通过理论中超导和非超导部分之间的对称性关系来理解。我们比较了由于接合处的临近诱导配对势和TDOS随距离x的变化关系。我们证明了TDOS(x)/TDOS(x→0)和配对势(x)/配对势(x→0)的空间幂律指数与各种本地和非本地相互作用参数的关系不同,这表明TDOS增强不能直接归因于LL中的临近诱导配对势。

英文摘要:

A recent study have shown that it is possible to have enhancement, in contrast to an expected suppression, in tunneling density of states (TDOS) in a Luttinger liquid (LL) which is solely driven by the non-local density-density interactions. Also, it is well known that a LL in proximity to a superconductor (SC) shows enhancement in TDOS in the vicinity of the junction in the zero energy limit. In this paper, we study the interplay of nonlocal density-density interaction and superconducting correlations in the TDOS in the vicinity of the SC-LL junction, where the LL maybe realized on the edge of an integer or a fractional quantum Hall state. We show that the TDOS enhancement in a LL quantum wire (QW) due to superconducting correlation at the junction can be farther amplified in presence of appropriate choice of non-local interaction parameters, which is demonstrated through a neat algebraic expression in the weak interaction limit. We also show that, in the full parameter regime comprising both the local and the non-local interaction, the region of enhanced TDOS for LL junction with "superconducting" boundary condition and that of "non-superconducting charge conserving" boundary condition (discussed in Phys. Rev. B 104, 045402 (2021)) are mutually exclusive. We show that this fact can be understood in terms of symmetry relation established between the superconducting and non-superconducting sectors of the theory. We compare the dependence of the proximity induced pair potential and TDOS as a function of distance $x$ from the junction. We demonstrate that the dependence of the spatial power law exponent for the `TDOS(x)/TDOS(x -> 0)' and the `pair-potential(x)/pair-potential(x -> 0)' are distinct function of the various local and non-local interaction parameters, which implies that the TDOS enhancement can not be directly attributed to the proximity induced pair potential in the LL.

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