Configurational dephasing in a weak-localization experiment
We have determined the dephasing time for the two-dimensional electron gas on the surface of a H2 crystal from low-field magnetoresistance measurements. We find that a moderate amount of helium gas above the H2 surface causes large increases in resistivity, but unexpectedly small negative magnetoresistance effects. We attribute this to a suppression of weak localization as a result of the dephasing effect of the thermal motion of helium atoms normal to the H2 surface. © 1989 The American Physical Society.