Strain-driven conducting domain walls in GaV4S8

Electrically conducting ferroelectric domain walls (DWs) show great potential as active elements in a new generation of nanoelectronic devices: their controlled nucleation, movement, and annhilation would allow for the deterministic reconfiguration of conductive pathways within such device. Conductive DWs are conventionally found in wide-gap ferroelectrics, where the conductivity arises from local changes in carrier density due to the accumulation of screening charges at polar discontinuities. We have recently discovered that DWs can be conductive also in narrow-gap materials with a strong charge-lattice coupling, such as the Mott insulator GaV4S8. Based on scanning probe measurements, we believe that the DW conductivity arises from the large surface reconstruction that accompanies the Jahn-Teller transition in this material. We propose to validate this hypothesis by performing scanning X-ray diffraction microscopy at DWs, measuring the strain in their vicinity,