Paring instability in the mixed state of a d-wave superconductor

作者：Jiang Hua^*; Liu Guo Zhu; Cheng Geng

来源：Physical Review B, 2009, 79(17): 174503.

DOI：10.1103/PhysRevB.79.174503

• d-wave superconductivity
• excitons
• high-temperature superconductors
• metal-insulator transition
• mixed state
• quasiparticles
• superfluidity
• thermal conductivity

We propose that an excitonic gap can be generated along nodal directions by Coulomb interaction in the mixed state of d-wave cuprate superconductors. In a superconductor, the Coulomb interaction usually cannot generate any fermion gap since its strength is weakened by superfluidity. It becomes stronger as superfluid density is suppressed by external magnetic field, and is able to generate a gap for initially gapless nodal quasiparticles beyond some critical field H(c). By solving the gap equation, it is found that the nodal gap increases with growing field H, which leads to a suppression of thermal conductivity at zero temperature. This mechanism naturally produces the field-induced thermal metal-insulator transition observed in transport experiments.

• 出版日期2009-5
• 单位中国科学技术大学