Hole mobility
= Hole mobility
{title2=$\mathbf v_h=\mu_h\mathbf E$}
The positive hole mobility is the magnitude of an <electron hole>'s weak-field <drift velocity> per unit <electric field>. In an isotropic relaxation-time model, $\mu_h=e\tau_h/m_h^*$, and its contribution to <electrical conductivity> is $ep\mu_h$. The sign is opposite to an electron's drift because the <electron hole> has positive charge.