Halide adsorption influences snapback distance in Scanning Tunnelling Microscope break junctions

Abstract

‘Snapback distance’ refers to the rapid increase in the size of the gap formed immediately after breaking an atomic-scale metallic contact. It is a commonly observed phenomenon in Scanning Tunnelling Microscope break junction (STM-BJ) and mechanically controlled break junction (MCBJ) experiments. Here, we show that the snapback distance measured for a gold break junction in pure water was significantly reduced in an electrolyte containing halide anions. In the case of Br⁻, experiments under electrochemical control provided clear evidence that this reduction was caused by halide adsorption on the surface of the gold.