Modeling Green's function measurements with two-tip scanning tunneling microscopy

Physical review. B./Physical review. B, vol. 102

Abstract

A double-tip scanning tunneling microscope with nanometer-scale tip separation has the ability to access the single-electron Green's function in real and momentum spaces based on second-order tunneling processes. Experimental realization of such measurements has been limited to quasi-one-dimensional systems due to the extremely small signal size. Here we propose an alternative approach to obtain such information by exploiting the current-current correlations from the individual tips and present a theoretical formalism to describe it. To assess the feasibility of our approach we make a numerical estimate for an $\ensuremath{\sim}25$-nm Pb nanoisland and show that the wave function in fact extends from tip to tip and the signal depends less strongly on increased tip separation in the diffusive regime than the one in alternative approaches relying on tip-to-tip conductance.

Authors 4

1. Maarten Leeuwenhoek Aachen

   Leiden University · Delft University of Technology

   Affiliation as printed

   Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, Netherlands

   Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333CA Leiden, Netherlands

2. Simon Gröblacher

   Delft University of Technology

   Affiliation as printed

   Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, Netherlands

3. Milan P. Allan Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333CA Leiden, Netherlands

4. Yaroslav M. Blanter

   Delft University of Technology

   Affiliation as printed

   Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, Netherlands