1/f noise of STM tunnel probe as a function of temperature

The tunneling probe used in Scanning Tunneling Microscopy (STM) has been recently proposed as displacement sensor for resonant gravitational‐wave antennas[1]. At present the performance of the tunnel probe as displacement sensor are limited by the 1/f noise in the tunnel current which, at room temperature, lowers of three orders of magnitude the expected sensitivity in the KHz range: preliminary results indicate that at liquid helium temperature the tunnel probe is a shot noise limited device. To understand the origin of the 1/f noise we are carrying on systematic measurements of the tunnel current noise as a function of the temperature and for different materials; the experimental results will be presented during the conference. Due to the quantum mechanical nature of the tunnel probe we believe that noise measurements as a function of the temperature can give also some useful information on the fundamental origin of the 1/f noise.