研究目的
Investigating the charge transport properties of a 20.5-nm-wide HgTe-based quantum well under hydrostatic pressure and perpendicular magnetic field.
研究成果
The study concludes that application of pressure to a wide HgTe quantum well alters its transport properties significantly. At ambient pressure, transport is well described by the two-band semiclassical model, while at elevated pressures, nonmonotonic pressure dependence of resistivity is observed. Above ≈14 kbar, sharp changes in resistance and magnetoresistance character may indicate significant changes in electronic structure. The study highlights the strong influence of disorder on transport in 2D electron-hole systems with small band overlap.
研究不足
The study is limited by the pressure range up to 15.1 kbar and the specific sample configuration. The interpretation of results is constrained by the models used and the potential for structural changes at high pressures.
1:Experimental Design and Method Selection:
The study involved systematic measurements of charge transport properties under hydrostatic pressures up to 15.1 kbar and perpendicular magnetic fields. The methodology included the use of a two-band semiclassical model for ambient pressure conditions and observations of nonmonotonic pressure dependence of resistivity at elevated pressures.
2:1 kbar and perpendicular magnetic fields. The methodology included the use of a two-band semiclassical model for ambient pressure conditions and observations of nonmonotonic pressure dependence of resistivity at elevated pressures.
Sample Selection and Data Sources:
2. Sample Selection and Data Sources: The samples were CdxHg1?xTe/HgTe/CdxHg1?xTe with a 20.5-nm-wide HgTe quantum well, grown by modified MBE technology on (100)-GaAs substrate.
3:5-nm-wide HgTe quantum well, grown by modified MBE technology on (100)-GaAs substrate.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: A Hall bar was lithographically defined for resistivity tensor measurements. A TiAu film gate electrode was used to vary the density of holes and electrons. Hydrostatic pressure was applied using a BeCu cell of the piston-cylinder type with PES-1 as a pressure-transmitting medium.
4:Experimental Procedures and Operational Workflow:
Resistivity was measured by conventional four probe ac lock-in technique. Pressure values were determined from the superconducting transition of a tin gauge. Magnetoresistance data were symmetrized and antisymmetrized by taking measurements in both magnetic field directions.
5:Data Analysis Methods:
The data were analyzed using the two-band semiclassical model and the Raikh and Glazman model for hopping conduction.
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