Niu, C (reprint author), Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China.
We construct the simplest gravitational dual model of a superconductor on Q-lattices. We analyze the condition for the existence of a critical temperature at which the charged scalar field will condense. In contrast to the holographic superconductor on ionic lattices, the presence of Q-lattices will suppress the condensate of the scalar field and lower the critical temperature. In particular, when the Q-lattice background is dual to a deep insulating phase, the condensation would never occur for some small charges. Furthermore, we numerically compute the optical conductivity in the superconducting regime. It turns out that the presence of Q-lattice does not remove the pole in the imaginary part of the conductivity, ensuring the appearance of a delta function in the real part. We also evaluate the gap which in general depends on the charge of the scalar field as well as the Q-lattice parameters. Nevertheless, when the charge of the scalar field is relatively large and approaches the probe limit, the gap becomes universal with omega(g) similar or equal to 9T(c) which is consistent with the result for conventional holographic superconductors.
Natural Science Foundation of China [11275208, 11305018, 11178002]
; Jiangxi young scientists (JingGang Star) program
; 555 talent project of Jiangxi Province
; Program for Liaoning Excellent Talents in University [LJQ2014123]