Zero-point plasmon motion in the extreme quantum limit in InSb

Abstract

Further experiments at helium temperatures are described on the anomalous NMR relaxation peak, first reported by Bridges and Clark, in the extreme quantum limit in doped InSb, extending the previously reported density range of the phenomenon up to 5 × 10 22 m −3 of donor electrons. New features of the anomaly, in particular an isotope effect, are reported. The large density range over which the effect has now been observed, taken with the new features, render many of the previous theories of the peak untenable. Based on the zero-point plasmon motion of the electron gas, we put forward an interpretation which appears to explain the various aspects of the phenomenon.