Photogalvanic effect induced by an electric field

Abstract

Light-induced charge transport that occurs in crystals containing centres with permanent dipole moment due to their polar orientation is considered. Principal attention is paid to the situation when such dipolar centres are oriented by application of an external electric field. In this case, we may regard the current generation as caused by an electric-field-induced photogalvanic effect. In contrast to conventional photogalvanic phenomena, the effect under consideration can be observed in crystals of arbitrary symmetry and even in any condensed matter containing photoactive dipolar centres. A remarkable feature of the effect is noncollinear orientation of the current vector with respect to the electric field vector, which is a consequence of the discrete set of orientations available for the dipole centres' positions. It is shown that this feature could significantly facilitate experimental observation of the electric-field-induced photogalvanic current. Here, a phenomenology description and qualitative model of the effect are presented and its possible impact on the effect of absolute negative conductivity is discussed.