Strange metal crossover in the doped holographic superconductor

Abstract

In a recent paper, Kiritsis and Li presented a holographic model to study the competition between different orders at finite doping in holographic superconductors. In the present work, we introduce fermions into such model and study the fermionic spectral functions in the normal phase at zero and finite temperatures. Combining analytic and numerical methods, we found that there is a crossover from a strange metal with short lived excitations at small doping, into a Fermi liquid with well defined quasiparticles at large doping. The critical doping at which excitations becomes long lived increases with temperature. The emerging phase diagram is qualitatively similar to that of High Temperature Superconductors.

Fermionic response in nonlinear arcsin electrodynamics

“…Even though for a given temperature the transition occurs on the specific value of momentum dissipation for different values of charge of the particle q, the qualitative behaviour does not depend on this variable q. This is similar to the normal metal to strange metal transition found in [22] where the transition occurred due to tuning of doping instead of a variation of the magnitude of axionic scalar.…”

“…As we have mentioned the dual boundary theory associated with this model admits a rich phase structure and it would be interesting to incorporate all of these phases in a single gravity theory. Another natural extension of the present work is to consider U (1) × U (1) gauge fields in this setup and introduce doping along the line of [22]. We would like to report on some of these in future.…”

“…To generalise this in the case of finite temperature, where r * = r h one considers the following equation in addition to (2.23) [16,22]…”

“…ν plays a central role in determining the nature of the Fermi surface. The lifetime of the fermionic excitations around the Fermi surface is given by [22] τ = ω −ν at zero temperature and τ ∼ T −2ν at finite temperature. As the lifetime of the excitation depends on ν, the metallic behaviour of the system is controlled by ν.…”

“…Charged Lifshitz black branes were considered in [19,20]. Effect of doping parameters on fermionic excitations in the holographic set up was studied in [21,22] and gives rise to transition between Fermi liquid to non-Fermi liquid phase. Similar studies of fermions in top down approach appear in [23][24][25][26][27][28].…”