Study on the formation mechanism of a complex domain structure in LiNbO3

Abstract

A complex domain structure in LiNbO3 is fabricated by proton exchange followed by heat treatment. Domain inversion at the +c and −c faces as well as reinversion in the inverted region near the +c surface are observed experimentally. The proton and lithium concentrations are measured by secondary ion mass spectroscopy. It is found that the proton profile peaks away from the surface due to indiffusion and outdiffusion. The domain inversion mechanism is discussed. An internal electric field model is proposed which is based on the concentration gradient of proton and lithium deficiency.