Geometric and Conventional Contribution to the Superfluid Weight in Twisted Bilayer Graphene.

作者: Xiang Hu , Timo Hyart , Dmitry I. Pikulin , Enrico Rossi

DOI: 10.1103/PHYSREVLETT.123.237002

关键词: SuperconductivitySuperfluidityMagic angleEffective mass (solid-state physics)GraphenePairingCondensed matter physicsBilayer grapheneQuantum geometryPhysics

摘要: By tuning the angle between graphene layers to specific “magic angles” the lowest energy bands of twisted bilayer graphene (TBLG) can be made flat. The flat nature of the bands favors the formation of collective ground states and, in particular, TBLG has been shown to support superconductivity. When the energy bands participating in the superconductivity are well isolated, the superfluid weight scales inversely with the effective mass of such bands. For flat band systems one would therefore conclude that even if superconducting pairing is …

参考文章(53)
E. Suárez Morell, J. D. Correa, P. Vargas, M. Pacheco, Z. Barticevic, Flat bands in slightly twisted bilayer graphene: Tight-binding calculations Physical Review B. ,vol. 82, pp. 121407- ,(2010) , 10.1103/PHYSREVB.82.121407
Sebastiano Peotta, Päivi Törmä, Superfluidity in topologically nontrivial flat bands. Nature Communications. ,vol. 6, pp. 8944- 8944 ,(2015) , 10.1038/NCOMMS9944
D. J. Scalapino, S. R. White, S. C. Zhang, Superfluid density and the Drude weight of the Hubbard model. Physical Review Letters. ,vol. 68, pp. 2830- 2833 ,(1992) , 10.1103/PHYSREVLETT.68.2830
Julie A. Bert, Beena Kalisky, Christopher Bell, Minu Kim, Yasuyuki Hikita, Harold Y. Hwang, Kathryn A. Moler, Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface Nature Physics. ,vol. 7, pp. 767- 771 ,(2011) , 10.1038/NPHYS2079
N. B. Kopnin, T. T. Heikkilä, G. E. Volovik, High-temperature surface superconductivity in topological flat-band systems Physical Review B. ,vol. 83, pp. 220503- ,(2011) , 10.1103/PHYSREVB.83.220503
G. Trambly de Laissardière, D. Mayou, L. Magaud, Numerical studies of confined states in rotated bilayers of graphene Physical Review B. ,vol. 86, pp. 125413- ,(2012) , 10.1103/PHYSREVB.86.125413
J. M. B. Lopes dos Santos, N. M. R. Peres, A. H. Castro Neto, Graphene bilayer with a twist: electronic structure. Physical Review Letters. ,vol. 99, pp. 256802- 256802 ,(2007) , 10.1103/PHYSREVLETT.99.256802
A. F. Hebard, A. T. Fiory, Evidence for the Kosterlitz-Thouless transition in thin superconducting aluminum films Physical Review Letters. ,vol. 44, pp. 291- 294 ,(1980) , 10.1103/PHYSREVLETT.44.291
Douglas J. Scalapino, Steven R. White, Shoucheng Zhang, Insulator, metal, or superconductor: The criteria. Physical Review B. ,vol. 47, pp. 7995- 8007 ,(1993) , 10.1103/PHYSREVB.47.7995
Julie A. Bert, Katja C. Nowack, Beena Kalisky, Hilary Noad, John R. Kirtley, Chris Bell, Hiroki K. Sato, Masayuki Hosoda, Yasayuki Hikita, Harold Y. Hwang, Kathryn A. Moler, Gate-tuned superfluid density at the superconducting LaAlO 3 /SrTiO 3 interface Physical Review B. ,vol. 86, pp. 060503- ,(2012) , 10.1103/PHYSREVB.86.060503