Surface electrical conductivity measurement system with micro-four-point probes at sub-Kelvin temperature under high magnetic field in ultrahigh vacuum

Abstract

We have constructed an ultrahigh vacuum system in which surface conductivity is measured in situ by microfour- point probe method down to 0.8 K, combined with conventional surface preparation/analysis capability. In order to reduce the data scattering due to changes of the probe spacing, we have employed a dual configuration method in which the combinations with current/voltage probes are switched. The surface-state superconductivity of Si(111)- ? 7 × ? 3-In surface superstructure was confirmed with the critical temperature of 2.8 K. The critical magnetic field was 0.3-0.4 T in the surface-normal direction. © 2012 The Surface Science Society of Japan.