A scanning tunnelling microscope tip sits above a metal surface with work function eV

PHYSICS · Subjective · Fermi University Physics · Quantum Mechanics · Wave mechanics in one dimension · Wave mechanics in one dimension

Quantum Mechanics: From the Photon to the Hydrogen Atom, Ch Free particles, wave packets and tunnelling

Problem

A scanning tunnelling microscope tip sits above a metal surface with work function

5.0

eV. Estimate the factor by which the tunnelling current falls if the tip is pulled back by

0.30

nm, treating the current as proportional to

e^{-2\kappa a}

and ignoring any change in the prefactor. Use

\hbar^2/2m_e = 0.0381

eV nm

^2