Fig. 2
The temperature and pressure-dependent resistances and conductances for BTS and BSTS. a, b Resistance as a function of temperature at fixed pressure for the two materials. The back squares are our experimental data, the red circles are the data fitted for the insulating bulk in the high temperature range by the equation of Rbul (T) = [R0bul exp[(T/T0)−0.25] and the green triangles are the surface state conductance, obtained from our experimental (black) data by subtracting the fitted bulk conductance extrapolated from the high temperature range (red). c, d The pressure and temperature dependence of the conductance of the TSS and the insulating bulk for BTS and BSTS, showing that the conductance of the bulk (Gbul) increases with both increasing pressure and temperature, while the conductance of TSS (Gsur) stays relatively constant with pressure and temperature
