Magnetoresistance and magnetic breakdown in the quasi-two-dimensional conductors (BEDT-TTF)2_2MHg(SCN)4_4[M=K,Rb,Tl]

The magnetic field dependence of the resistance of (BEDT-TTF)$_2$MHg(SCN)$_4$[M=K,Rb,Tl] in the density-wave phase is explained in terms of a simple model involving magnetic breakdown and a reconstructed Fermi surface. The theory is compared to measurements in pulsed magnetic fields up to 51 T. The value implied for the scattering time is consistent with independent determinations. The energy gap associated with the density-wave phase is deduced from the magnetic breakdown field. Our results have important implications for the phase diagram.Comment: 5 pages, RevTeX + epsf, 3 figures. To appear in Physical Review B, Rapid Communications, September 15, 199

Magneto-oscillations in the high-magnetic-field state of (TMTSF)(2)ClO4

We report a systematic study of the anomalous rapid oscillation (RO) phenomena in the quasi-one-dimensional organic metal (TMTSF)(2)ClO4 in pulsed magnetic fields up to 51 T. We argue that the temperature and magnetic-field dependence of the RO amplitudes in the high-field state result from the reconstructed, nested Fermi surface topology at low temperatures in high magnetic fields. In this topology, the RO amplitudes depend on competing magnetic breakdown and Bragg reflection probabilities, along with Lifshitz-Kosevich reduction factors

Far-infrared measurements of cyclotron resonance and impurity transitions in bulk n-GaAs in pulsed magnetic fields

The photoconductive response of n-GaAs has been measured under laser radiation in the wavelength range 71 to 513 /spl mu/m at temperatures as low as 400 mK and at magnetic fields as high as 42 T. A rich variety of spectral features are observed: cyclotron resonance, transitions associated with D/sup -/, and transitions to stable and metastable hydrogenic states. The use of a pulsed magnet has extended the magnetic field range over which data is available by a factor of three

Central-cell corrections for Si and S in GaAs in a strong magnetic field

The central-cell correction has been determined experimentally for the two donor impurities S and Si in GaAs. Data have been obtained for magnetic fields to 39 T, corresponding to γ~6. The observed behavior is in good agreement with theory. The analysis permits accurate evaluation of zero-field central-cell corrections, yielding 0.110 and 0.059 meV for S and Si, respectively

Far-infrared laser photoconductivity of n-GaAs multiple quantum wells in a pulsed magnetic field

Far-infrared laser magnetospectroscopy of a multiple quantum well (MQW) structure, δ-doped with Si donors in both the wells and the barriers, has been carried out over the energy range 6–18 meV using a pulsed magnet, the calibration of which is confirmed by cyclotron resonance measurements on bulk n-GaAs. Apart from cyclotron resonance, the MQW exhibits a spectral feature at a magnetic field exceeding that of the 1s→2p+ bulk transition at the same laser wavelength. This feature is attributed to a transition involving electrons in the well which are bound to donor sites in the barriers