Electric-Field-Induced Infrared Absorption in Diamond

Abstract

In the presence of an external electric field, certain Raman-active vibration modes in diamond-type crystals also become infrared active, giving rise to an absorption proportional to the first-order change in the electronic polarizability per unit cell with the relative displacement of atoms, $\frac{\partial \alpha }{\partial u}$. We have observed such a transmission minimum and from its characteristics we have determined the electric-field-induced effective ionic charge and $\frac{\partial \alpha }{\partial u}$.