Emergence of strongly correlated electronic states driven by the Andreev bound state in d-wave superconductors
Emergence of strongly correlated electronic states driven by the Andreev bound state in d-wave superconductors
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d 波超导体中安德烈夫束缚态驱动的强相关电子态的出现
DOI：
10.1103/physrevb.101.075114
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发表时间：
2020
影响因子：
3.7
通讯作者：
Kontani Hiroshi
中科院分区：
文献类型：
--
作者：
Matsubara Shun;Kontani Hiroshi
在a波超导体的开放（1，1）边形成表面Andreev束缚态（ABS）时，局域态密度增加。因此，可能发生强电子关联和剧烈现象。然而，ABS对电子关联的影响的理论研究尚未进行。为了理解这些效应，我们研究了在体波带隙存在的情况下具有开放（1，1）边的大团簇Hubbard模型。在真实的空间中，我们采用无规相位近似和修正的涨落交换近似计算了自旋极化率。我们发现，在（1，1）边附近，由于ABS，发生了剧烈的铁磁（FM）波动。此外，随着温度的降低，系统迅速接近磁序相略低于体波超导（SC）的转变温度。在这种情况下，FM波动预计会引起有趣的现象，如边缘诱导三重态SC和量子临界现象。
As the surface Andreev bound state (ABS) forms at the open (1,1) edge of a-wave superconductor, the local density of states increases. Therefore, a strong electron correlation and drastic phenomena may occur. However, a theoretical study on the effects of the ABS on the electron correlation has not been performed yet. To understand these effects, we study the large-cluster Hubbard model with an open (1,1) edge in the presence of a bulk-wave gap. We calculate the site-dependent spin susceptibility by performing the random-phase approximation and modified fluctuation-exchange approximation in real space. We find that near the (1,1) edge, drastic ferromagnetic (FM) fluctuations occur owing to the ABS. In addition, as the temperature decreases, the system rapidly approaches a magnetic-order phase slightly below the transition temperature of the bulk-wave superconductivity (SC). In this case, the FM fluctuations are expected to induce interesting phenomena such as edge-induced triplet SC and quantum critical phenomena.