Magnetotransport in C-doped AlGaAs heterostructures

Abstract

High-quality C-doped p-type AlGaAs heterostructures with mobilities exceeding 150 000 cm$^2$/Vs are investigated by low-temperature magnetotransport experiments. We find features of the fractional quantum Hall effect as well as a highly resolved Shubnikov-de Haas oscillations at low magnetic fields. This allows us to determine the densities, effective masses and mobilities of the holes populating the spin-split subbands arising from the lack of inversion symmetry in these structures.Comment: 3 pages, 4 figure

Strong spin–orbit interactions in carbon doped p-type GaAs heterostructures

“…SO interactions are expected to be very strong in p-type GaAs heterostructures, due to the p-like symmetry of the states at the top of the valence band and the high effective mass of the holes. In addition, the p-like symmetry of hole states ensures that they are weakly coupled to nuclear spins, which could provide long spin coherence times.Carbon doped p-type GaAs/AlGaAs heterostructures grown in the (1 0 0) direction are particularly interesting due to the high mobility and strong SO interactions measured in these systems [1]. We report on magnetoresistance measurements on a two-dimensional hole gas (2DHG) created 45 nm below the surface of a C-doped GaAs/AlGaAs heterostructure.…”

“…Carbon doped p-type GaAs/AlGaAs heterostructures grown in the (1 0 0) direction are particularly interesting due to the high mobility and strong SO interactions measured in these systems [1]. We report on magnetoresistance measurements on a two-dimensional hole gas (2DHG) created 45 nm below the surface of a C-doped GaAs/AlGaAs heterostructure.…”

“…3. The positive, parabolic magnetoresistance is characteristic of the classical Drude magnetoresistance in a system with two subbands of different mobilities [4,1].…”

Evidence for localization and 0.7 anomaly in hole quantum point contacts

“…The host heterostructure consists of a 5 nm undoped GaAs cap layer, followed by a 15 nm thick, homogeneously C-doped layer of AlGaAs separated from the 2DHG formed in the electronically isotropic (100) plane by a 25 nm thick, undoped AlGaAs spacer layer [25]. Prior to sample fabrication the quality of the 2DHG (n = 4×10 11 cm −2 , µ = 120'000 cm 2 /Vs) was characterized by standard magnetotransport measurements at 4.2 K [26]. Typical values for the interaction parameter r s = E int /E F are r s > 5.…”

Rashba-coupling modelling for two-dimensional and high-order Rashba Hamiltonian for one-dimensional confined heavy holes

“…Besides, pursuing a validation of our modelling approach, a comparison with some relevant analytical [12], experimental [10,11,[28][29][30][31][32] and numerical [10,11] contributions, had been included. In the case of experimental measurements the samples are of the type: Al x Ga 1−x As/GaAs, for several values of molar composition x and acceptor doping.…”