Measuring the Au(111) surface state at the solid–liquid interface

We present the first direct observation of an occupied noble metal surface state at the metal/liquid interface. The Au(111) Shockley-like surface state was measured by scanning tunneling spectroscopy (STS) at the Au(111)/n-tetradecane interface. These results show that the surface state of gold survives in a liquid environment, and can be probed by STS. More generally it indicates that STS can be used to study electronic properties of surfaces at the solid/liquid interface, and that spectra can be directly compared to measurements and calculations of a surface’s electronic structure in ultra-high vacuum.