Thermoelectric detection of Andreev states in unconventional superconductors
Thermoelectric detection of Andreev states in unconventional superconductors
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DOI：
10.1103/physrevresearch.2.043388
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发表时间：
2020-08
影响因子：
4.2
通讯作者：
Tony Savander;S. Tamura;C. Flindt;Yukio Tanaka;P. Burset
中科院分区：
文献类型：
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作者：
Tony Savander;S. Tamura;C. Flindt;Yukio Tanaka;P. Burset
我们从理论上描述了热电效应，这是完全由于Andreev过程涉及通过电子和空穴的耦合形成库珀对。Andreev热电效应可以发生在弹道铁磁体-超导体结中，铁磁体上具有主导的超导邻近效应，并且它对非常规超导体中出现的表面态非常敏感。我们认为在二维和三维的混合结证明，热电电流总是在超导体表面的低能量Andreev束缚态的存在下逆转。微观分析的邻近诱导的配对表明，热电效应只会出现，如果偶数和奇数频率的库珀对共存于混合的单重态和三重态。我们的结果是联合收割机磁性和超导性相结合的系统中涌现现象丰富性的一个例子，它们为探索非常规超导体中的奇异表面态开辟了一条途径。
We theoretically describe a thermoelectric effect that is entirely due to Andreev processes involving the formation of Cooper pairs through the coupling of electrons and holes. The Andreev thermoelectric effect can occur in ballistic ferromagnet-superconductor junctions with a dominant superconducting proximity effect on the ferromagnet, and it is very sensitive to surface states emerging in unconventional superconductors. We consider hybrid junctions in two and three dimensions to demonstrate that the thermoelectric current is always reversed in the presence of low-energy Andreev bound states at the superconductor surface. A microscopic analysis of the proximity-induced pairing reveals that the thermoelectric effect only arises if even and odd-frequency Cooper pairs coexist in mixed singlet and triplet states. Our results are an example of the richness of emergent phenomena in systems that combine magnetism and superconductivity, and they open a pathway for exploring exotic surface states in unconventional superconductors.