Giant Shubnikov-de Haas Oscillations with V-Shaped Minima in a High-Mobility Two-Dimensional Electron Gas: Experiment and Phenomenological Model

Abstract

Giant Shubnikov-de Haas oscillations (SdHO) with V-shaped minima are experimentally studied in a high-mobility two-dimensional electron gas based on GaAs/AlGaAs heterostructures. A phenomenological model with two parameters (transport momentum relaxation time ${\tau }_{\text{tr}}$ and quantum scattering time ${\tau }_q$) is developed, accurately describing experimentally measured magnetoresistance over an unexpectedly wide range of magnetic fields (up to 3.5 T) and temperatures (from 2 K to 15 K). The model combines: (i) a quasiclassical density of states with a magnetic-field-dependent Gaussian broadening of Landau levels, (ii) a momentum relaxation time scaling with the density of states, and (iii) oscillations of the Fermi level at a fixed electron density. This model reproduces V-shaped oscillation minima with zero-resistance points, a smooth background of positive magnetoresistance, and enables the extraction of ${\tau }_q$ and ${\tau }_{\text{tr}}$ even in microstructures where ballistic and viscous effects dominate at low fields. As expected, the temperature dependence reveals that ${\tau }_{\text{tr}}$ scales inversely with temperature due to acoustic phonon scattering, while ${\tau }_q$ remains temperature-independent.

References in corpus (10)

• Theory of microwave-induced oscillations in the magnetoconductivity of a 2D electron gas
• Measurements of the density-dependent many-body electron mass in 2D GaAs/AlGaAs Heterostructures
• Colossal negative magnetoresistance in a 2D electron gas
• Shubnikov-de Haas oscillations in GaAs quantum wells in tilted magnetic fields
• The effect of oscillating Fermi energy on the line shape of the Shubnikov-de Haas oscillation in a two dimensional electron gas
• Quantum Oscillations of the Quasiparticle Lifetime in a Metal
• Non-linear Transport Phenomena and Current-induced Hydrodynamics in Ultra-high Mobility Two-dimensional Electron Gas
• Positive Quantum Magnetoresistance in Tilted Magnetic Field
• Temperature Dependence of Electron Viscosity in Superballistic GaAs Point Contacts
• Slip electron flow in GaAs microscale constrictions