Low-energy subgap states and the magnetic flux periodicity in d-wave superconducting rings.
Low-energy subgap states and the magnetic flux periodicity in d-wave superconducting rings.
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DOI：
10.1103/physrevlett.100.177003
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发表时间：
2007-11
影响因子：
8.6
通讯作者：
Y. Barash
中科院分区：
文献类型：
--
作者：
Y. Barash
用解析的方法，得到了由Aharonov-Bohm磁通量引导的d波超导环中低能准粒子亚隙态的波函数。各自的能量在小磁通量下最接近中缝位置，并且由于超电流产生的多普勒频移而偏离费米表面。多普勒位移的零能态导致环在小通量下的顺磁响应。这些状态只存在于库柏对质心角动量为偶数的情况下，与最近的数值研究一致。d波环中的宏观量子效应导致h/2e周期被打破，只保留了随磁通量变化的超电流的h/e周期行为。
Wave functions of low-energy quasiparticle subgap states in d-wave superconducting rings, threaded by an Aharonov-Bohm magnetic flux, are found analytically. The respective energies are closest to the midgap position at small magnetic fluxes and deviate from the Fermi surface due to the Doppler shift, produced by the supercurrent. The Doppler-shifted zero-energy states result in a paramagnetic response of the ring at small fluxes. The states exist only for even angular momenta of the center of mass of Cooper pairs, in agreement with recent numerical studies of the problem. This macroscopic quantum effect in d-wave rings results in broken h/2e periodicity, retaining only the h/e periodic behavior of the supercurrent with varying magnetic flux.