Strong Correlation Effects on Surfaces of Topological Insulators via Holography

We investigate effects of strong correlation on the surface state of topological insulator (TI). We argue that electrons in the regime of crossover from weak anti-localization to weak localization, are strongly correlated and calculate magneto-transport coefficients of TI using gauge gravity principle. Then, we examine, magneto-conductivity (MC) formula and find excellent agreement with the data of chrome doped Bi${}_2$Te${}_3$ in the crossover regime. We also find that cusp-like peak in MC at low doping is absent, which is natural since quasi-particles disappear due to the strong correlation.