2016年12月
Superconductivity in repulsively interacting fermions on a diamond chain: Flat-band-induced pairing
PHYSICAL REVIEW B
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- 巻
- 94
- 号
- 21
- 開始ページ
- 214501
- 終了ページ
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1103/PhysRevB.94.214501
- 出版者・発行元
- AMER PHYSICAL SOC
To explore whether a flat-band system can accommodate superconductivity, we consider repulsively interacting fermions on the diamond chain, a simplest possible quasi-one-dimensional system that contains a flat band. Exact diagonalization and the density-matrix renormalization group are used to show that we have a significant binding energy of a Cooper pair with a long-tailed pair-pair correlation in real space when the total band filling is slightly below 1/3, where a filled dispersive band interacts with the flat band that is empty but close to E-F. Pairs selectively formed across the outer sites of the diamond chain are responsible for the pairing correlation. At exactly 1/3-filling an insulating phase emerges, where the entanglement spectrum indicates the particles on the outer sites are highly entangled and topological. These come from a peculiarity of the flat band in which "Wannier orbits" are not orthogonalizable.
- リンク情報
- ID情報
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- DOI : 10.1103/PhysRevB.94.214501
- ISSN : 2469-9950
- eISSN : 2469-9969
- ORCIDのPut Code : 49418675
- Web of Science ID : WOS:000389024000002