Cyclotron Resonance

Abstract

AbstractThis article reviews the technique and phenomenon of cyclotron resonance (CR). CR is a method for measuring the effective masses of charge carriers in solids and is by far the most direct and accurate method for providing such information. In the 1950s, the first CR studies were carried out in germanium and silicon crystals, which, in conjunction with the effective mass theory, successfully determined the band‐edge parameters for these materials with unprecedented accuracy. Since then, CR has been investigated in a large number of elementary and compound materials and their alloys and heterostructures. Quantum mechanically, CR can be viewed as a transition between adjacent Landau levels. In real solids, Landau levels are generally not equally spaced since the energy dispersion relation is not generally given by a simple parabolic dispersion relation, and, thus, effective masses are energy dependent as well as direction dependent. A detailed comparison between theory and experiment on quantum CR can provide a critical test of the band theory of solids. As a secondary purpose, one can also use CR to study carrier scattering phenomena in solids by examining the scattering. As the frequency of scattering events increases, CR linewidth increases, and, eventually, CR becomes unobservable when scattering occurs too frequently. Temperature and magnetic field dependence of CR linewidth provides insight into dominant scattering mechanisms.