# Hall effect in hole doped cupates

There is an interesting $T$ dependence in the Hall coefficient ^{[1]}, as shown in Fig 1. One can estimate the density of holes, $n_{\rm H}$, from measurements of the Hall coefficient with the formula $R_{\rm H}=1/n_{\rm H}ec$. The data imply that $n_{\rm H}$ increases with temperature. The temperature-dependent Hall effect data with the formula ^{[2]}

$$ n_{\rm H}(x,T) = n_0(x) + n_1(x)e^{-\Delta(x)/T}. $$

As shown in Fig. 2, the temperature-independent component, $n_0$, is proportional to $x$ for low doping. The gap $\Delta$ for the thermally-excited carriers is shown in Fig.3; it is quantitatively quite similar to the antinodal *pseudogap* from ARPES measurements.