Quantum Interference of Electron Waves in a Normal Metal

Abstract

Using a very pure single crystal of magnesium we have observed large-amplitude oscillations in the transverse magnetoresistance which result from the direct interference of normal-state electron waves. The amplitudes of these interference oscillations appear to be independent of the $\mathrm{kT}$ broadening of the Fermi distribution. The primary result of our experiment shows that these waves are phase coherent at 1.2\ifmmode^\circ\else\textdegree\fi{}K over macroscopic distances of at least 0.01 mm; this corresponds to a quasiparticle lifetime of at least 2 \ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}11}$ sec.