A path integral approach to electronic friction of a nanometer-sized tip scanning a metal surface

Yang Wang,Yu Jia

Figure 3. The imaginary part of the in-out amplitude as a function of the relative velocity, v, for the typical case $\varepsilon =0.3,J=0.1,0.2,0.4,0.5,\tfrac{1}{2{m}^{* }}=0.3$, in units of 4πUV2ΩT.