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Composite fermions in 2 x 10{sup 6} cm{sup 2}/Vs mobility A1GaAs/GaAs heterostructures grown by MOCVD

Description: Recent growth by MOCVD (metalorganic chemical vapor deposition) of 2.0x10{sup 6} cm{sup 2}/Vs mobility heterostructures are reported. These mobilities, the highest reported to date, are attributed to use of tertiarybutylarsine as the arsenic precursor. Measurements in tilted magnetic fields of the fractional quantum Hall effect states near filling factor 3/2 are consistent with a spin-split composite fermion (CF) model proposed earlier. Extracted values of the product of the CF g-factor and CF effective mass agree with values previously obtained for MBE samples.
Date: December 31, 1996
Creator: Simmons, J.A., Chui, H.C., Harff, N.E., Hammons, B.E. & Du, R.R., Zudov, M.A.
Partner: UNT Libraries Government Documents Department

Composite fermions in 2 {times} 10{sup 6} cm{sup 2}/Vs mobility AlGaAs/GaAs heterostructures grown by MOCVD

Description: The authors report on the recent growth by MOCVD of 2.0 {times} 106 cm2/Vs mobility heterostructures. These mobilities, the highest reported to date, are attributed to the use of tertiarybutylarsine as the arsenic precursor. Measurements in tilted magnetic fields of the fractional quantum Hall effect (FQHE) states near filling factor 3/2 are consistent with a spin-split composite fermion (CF) model proposed earlier. The extracted values of the product of the CF g-factor and CF effective mass agree with values previously obtained for MBE samples.
Date: August 1, 1996
Creator: Simmons, J.A.; Chui, H.C.; Harff, N.E.; Hammons, B.E.; Du, R.R. & Zudov, M.A.
Partner: UNT Libraries Government Documents Department

A new type of magnetoresistance oscillations: Interaction of a two-dimensional electron gas with leaky interface phonons

Description: The authors report a new type of oscillations in magnetoresistance observed in high-mobility two-dimensional electron gas (2DEG), in GaAs-AIGaAs heterostructures. Being periodic in 1/B these oscillations appear in weak magnetic field (B < 0.3 T) and only in a narrow temperature range (3 K < T < 7 K). Remarkably, these oscillations can be understood in terms of magneto-phonon resonance originating from the interaction of 2DEG and leaky interface-acoustic phonon modes. The existence of such modes on the GaAs:AIGaAs interface is demonstrated theoretically and their velocities are calculated. It is shown that the electron-phonon scattering matrix element exhibits a peak for the phonons carrying momentum q = 2k{sub F} (k{sub F} is the Fermi wave-vector of 2DEG).
Date: May 11, 2000
Creator: ZUDOV,M.A.; PONOMAREV,I.V.; EFROS,A.L.; DU,R.R.; SIMMONS,JERRY A. & RENO,JOHN L.
Partner: UNT Libraries Government Documents Department

Observation of Microwave Induced Zero-Conductance State in Corbino Rings of a Two-Dimensional Electron System

Description: Using Corbino samples they have observed oscillatory dc conductance in a high-mobility two-dimensional electron system when it is subjected to crossed microwave and magnetic fields. At the strongest of the oscillation minima the conductance is found to be vanishingly small, indicating a macroscopic insulating state associated with this minimum. With increasing voltage bias, a crossover from Ohmic to electron-heating regime is observed.
Date: August 29, 2003
Creator: Yang, C. L.; Pfeiffer, M. A.; Knuttila, T. A.; Du, R. R.; Pfeiffer,, L. N. & West, K. W.
Partner: UNT Libraries Government Documents Department