Tip induced changes of atomic scale images of the vanadiumpentoxide surface

We have measured atomic resolution scanning tunnelling microscopy images of V2O5. The layered compound V2O5 is a strongly anisotropic material with the layers parallel to the (ab) plane. Although V2O5 is a semiconductor with an optical gap of 2.3 eV an impurity band allows STM measurements with a good signal to noise ratio. Here we present atomic scale images of the V2O5 surfaces. The images show the periodicity of the bulk unit cell, but we observe various surface modifications, which transform into each other during scanning of the surface.