Cyclotron resonance of electrons in localized surface states

The distribution of dipole strength is calculated for a system of electrons moving in a twodimensional surface subband in the presence of a magnetic field. At low densities, where an appreciable part of the electrons occupy localized states the cyclotron resonance exhibits a characteristic field and density dependent structure. The observed drop of the apparent cyclotron mass in Si (100) surfaces is described. The effective activation energy is calculated. From the mobility data in the activated conduction regime it is concluded that only about 20% of the localized states have a localization range of the order of 100 Å or less.     

Cyclotron resonance of electrons and holes in TlBr

Cyclotron resonance measurements on TlBr with circularly polarized waves at 34 GHz show the presence of an electron resonance at (0.52 ± 0.03)m_o and a hole resonance at (0.70 ± 0.03)m_o. Mobilities of both electrons and holes are determined in the temperature range 6.5°K to 14°K.     

Anticrossing phenomena in a resonator with 2D electrons on liquid helium

We have investigated the details of the eigenmode for a resonator containing a two-dimensional electron system (2DES) formed on the surface of liquid helium. We show that anticrossing phenomena occur near the crossing point ω₀=ω_c, where ω₀ is the eigenmode of the resonator and ω_c is the cyclotron frequency. The structure of the coupling constant is established. It is a flexible parameter, i.e., sensitive especially to magnetic field and electron density. A finite coupling leads to a perturbation, δω, of the eigenmode of the resonator in presence of the 2DES. Corresponding calculations and measurements of δω are presented. The theory fits the experimental data. The influence of anticrossing on the cyclotron resonance absorption line shape is demonstrated.     

Cyclotron resonance of two-dimensional electrons forming wigner crystal

The cyclotron resonance peak shape is analysed for two-dimensional electrons interacting with surface vibrations of a medium. Explicit expressions for the broadening and shift of the peak are obtained at low and high electron densities.     

Cyclotron resonance studies on bulk and two-dimensional conduction electrons in InSe

Cyclotron resonance is reported for both bulk electrons and electrons bound to charged defect planes in the layer compound InSe. At temperatures below 20 K all carriers present are bound to defect planes and behave as two-dimensional accumulation layers. At higher temperatures the electrons are excited into bulk regions between the defects, and show three-dimensional, bulk behaviour. The conduction band is shown to exhibit an “anomalous anisotropy” with m_∥ = 0.08m₀ and m_⊥ = 0.14m₀. The bound, two-dimensional carriers exhibit a strong non-parabolicity, and show a band edge mass m_⊥ = 0.13 which is considerably lower than the bulk value possibly due to a reduction in the polaron constant in the degenerate electron gas.     

Cyclotron resonance of inversion electrons on InSb in tilted magnetic fields

Cyclotron resonance (CR) of inversion electrons on InSb is studied in magnetic fields tilted away from the surface normal. Particularly, a pronounced splitting of the CR signals into two distinct resonances is observed. When the magnetic field is parallel to the inversion layer one of the two resonances vanishes and the other evolves into a bulk like CR at sufficiently low electron densities and in sufficiently high resonance magnetic fields. The different absorption modes are explained by a strong coupling of the electric and magnetic quantization on InSb in tilted magnetic fields.     

Cyclotron resonance of electrons and holes in electric surface subbands of tellurium

We present first measurements of the submillimeter-cyclotron resonance of electrons and holes in electric surface subbands of tellurium. From the resonance in the inversion layer we have obtained for the magnetic field paralled to the trigonal axis, the cyclotron mass of the surface electron m_ce = (0.117 ± 0.002)m₀. The resonance of the accumulation layer splits and suggests the contribution of different nonparabolic subbands.     

Shift in cyclotron resonance of electrons on liquid helium surfaces

We calculate the increase in cyclotron resonance frequency for electrons trapped within dimples on a liquid helium surface, when a vertical electric field is applied in addition to the strong vertical magnetic field.     

Cyclotron resonance study of conduction electrons in n-type indium antimonide under a strong magnetic field—II: Hot electrons

A system of hot electrons in the n-InSb under the application of a strong magnetic field has been studied by far IR cyclotron resonance. A three band model and an energy independent scattering time were assumed in analyzing the line shape variation with electric field applied either parallel or perpendicular to the magnetic field. Two kinds of electron temperature, inter- and intra-subband, were introduced to describe the electron distribution in energy space. The electron distribution function was found to deviate from an essentially Maxwellian form in the manner predicted by Yamada and Kurosawa. A remarkable difference exists between the two geometries: E∥H and E⊥U. A brief survey of cyclotron emission, and the reverse process of hot electron cyclotron absorption, is summarized at the end as an addendum.     

Cyclotron resonance in a two-dimensional semimetal

Cyclotron resonance in a two-dimensional semimetal has been studied theoretically, keeping in mind recent experiments reported in Z. D. Kvon, S. N. Pamilov, S. D. Ganichev, et al., in Proceedings of the 14th International Conference on Narrow Gap Semiconductors and Systems (Sendai, Japan, 2009). Since the size of the sample is finite, the exciting microwave inhomogeneous and there is a plasma shift of resonance frequency. There are two magnetoplasmon branches in a two-component system, which undergo pseudocrossing under the found criterion. Resonance frequencies and intensities of absorption peaks have been found. The latter are complicated functions of the electron and hole densities.     

Cyclotron resonance of hot electrons and nonlinear transport phenomena in n-type indium antimonide

Impurity states and nonlinear transport phenomena in n-type indium antimonide under strong magnetic fields have been extensively studied at liquid helium temperatures through H₂O laser cyclotron resonance combined with d.c. measurements. A new type cyclotron resonance with modulation by pulsed electric field, or PEM-CR, has been utilized throughout. Origin of several weak transitions so far indefinite has been identified. Existence of the donor binding state in a magnetic field as low as 2·85 kOe for the excess donor concentration N_D ? N_A = 2 × 10¹³ cm^?3 is experimentally confirmed. Joint determination of resistivity and carrier distribution in the energy space has yielded a fair success in separating the mechanisms for the nonlinear transport behavior.     

Cyclotron resonance in quasi-two-dimensional conductors

A theoretical analysis is made of the resonant absorption of RF electromagnetic wave energy in layered conductors having a quasi-two-dimensional electron energy spectrum. An analysis is made of the influence of possible drift of carriers into the conductor and their Fermi-liquid interaction on the position of the cyclotron resonance lines. A reason is given for the substantial difference between the cyclotron effective masses determined from the temperature dependence of the amplitude of the Shubnikov-de Haas oscillations and from measurements of the cyclotron resonance frequencies in [5–7]. It is shown that by means of an experimental investigation of cyclotron resonance in a magnetic field parallel to the layers, it is possible to find the carrier velocity distribution at the Fermi surface in layered organic conductors.     

Cyclotron resonance in bilayer graphene

We present the first measurements of cyclotron resonance of electrons and holes in bilayer graphene. In magnetic fields up to B=18 T, we observe four distinct intraband transitions in both the conduction and valence bands. The transition energies are roughly linear in B between the lowest Landau levels, whereas they follow square root[B] for the higher transitions. This highly unusual behavior represents a change from a parabolic to a linear energy dispersion. The density of states derived from our data generally agrees with the existing lowest order tight binding calculation for bilayer graphene. However, in comparing data to theory, a single set of fitting parameters fails to describe the experimental results.     

Cyclotron resonance in a semiconductor in a steady electric field

The classical kinetic equation is solved to find the carrier distribution in the valence band for germanium in cyclotron resonance, the carriers being generated by the electric field. Negative power absorption is demonstrated.I am indebted to V. G. Veselago for proposing the topic and to Yu. M. Kagan for a discussion.