File: TCCRB5.TEX at 14:58 on August 12, 1999 TWO-COMPONENT CYCLOTRON RESONANCE IN BILAYER QUANTUM HALL SYSTEMS

Kohn's theorem [1] is no longer applicable to multi-component systems, which consist of more than two kinds of electrons with di erent cyclotron frequencies. In such systems, cyclotron resonance (CR) is generally modi ed by electron-electron interaction in its positions and lineshapes. In this paper, interaction e ects on two-component CR is studied in asymmetric double quantum well (QW) systems in quantum Hall regime by means of a numerical diagonalization method. Interesting behaviors were observed in CR in Si (100) inversion layers, in which there are two kinds of electrons with di erent masses because of multi-valley structure of conduction band [2]. A Fermi-liquid theory approach predicted that electron-electron interaction gives rise to a mode repulsion with intensity transfer [3]. A Boltzmann equation approach showed that electron-electron scattering important at high temperatures leads to merging of two peaks, i.e., a motional narrowing [4]. In GaAs/AlGaAs heterostructures, an up-spin electron has slightly larger cyclotron frequency than a down-spin electron. In the extreme quantum limit, an interesting mode repulsion behavior was observed experimentally [5] and analyzed theoretically [6]. In previous papers [7,8] interaction e ects on spin-split CR were studied in a quantum Hall regime. It was shown that spectra are categorized into three types of behaviors, a positive mode repulsion, a negative mode repulsion, and a motional narrowing, depending sensitively both on the lling factor of upand down-spin electrons and on temperature. In this paper, we shall consider two-component CR in bilayer systems where the strength of intralayer and interlayer interactions can be controlled independently. Some experiments have been performed in such systems and shown intriguing results [9].