Static conductivity of charged domain wall in uniaxial ferroelectric-semiconductors

TL;DR

This study uses Landau-Ginzburg-Devonshire theory to numerically analyze the static conductivity of charged domain walls in uniaxial ferroelectric-semiconductors, revealing significant conductivity variations based on domain wall inclination and charge accumulation.

Contribution

It provides a detailed numerical analysis of static conductivity in charged domain walls considering electron and hole densities, extending understanding of charge distribution effects in ferroelectric-semiconductors.

Findings

Conductivity increases by up to 3 orders of magnitude at inclined head-to-head walls.

Two regions of charge accumulation exist near tail-to-tail walls, affecting conductivity.

Conductivity at tail-to-tail walls is lower due to low hole mobility.

Abstract

Using Landau-Ginzburg-Devonshire theory we calculated numerically the static conductivity of both inclined and counter domain walls in the uniaxial ferroelectrics-semiconductors of n-type. We used the effective mass approximation for the electron and holes density of states, which is valid at arbitrary distance from the domain wall. Due to the electrons accumulation, the static conductivity drastically increases at the inclined head-to-head wall by 1 order of magnitude for small incline angles theta pi/40 by up 3 orders of magnitude for the counter domain wall (theta=pi/2). Two separate regions of the space charge accumulation exist across an inclined tail-to-tail wall: the thin region in the immediate vicinity of the wall with accumulated mobile holes and the much wider region with ionized donors. The conductivity across the tail-to-tail wall is at least an order of magnitude smaller than the one of the head-to-head wall due to the low mobility of holes, which are improper carries. The results are in qualitative agreement with recent experimental data for LiNbO3 doped with MgO.