Abstract
The magnetotransport properties of massless Dirac fermions in a gapless HgTe quantum well are investigated. In samples with narrow channels, a large negative magnetoresistance with a Lorentzian profile is observed, which is interpreted as a manifestation of electron viscosity due to electron-electron interaction. Comparison of experiment with theory yields the shear stress relaxation time of the Dirac fermions caused by electron-electron scattering.
Highlights
In many cases, for the description of phenomena in solidstate structures, the approximation of noninteracting electrons turns out to be inapplicable and the electron-electron (e-e) interaction, which is one of the oldest problems in solid state physics, acquires a key role [1,2]
In samples with narrow channels, a large negative magnetoresistance with a Lorentzian profile is observed, which is interpreted as a manifestation of electron viscosity due to an electron-electron interaction
A comparison of experiment with theory yields the shear stress relaxation time of the Dirac fermions caused by electron-electron scattering
Summary
The experimental structures were identical Hall bar devices consisting of three consecutive sections with different widths. The distance between the voltage probes was L = 12, 30, 100 μm, (Fig. 1). A macroscopic Hall bar device with eight voltage probes was examined. This Hall bar had a width W of 50 μm and three consecutive segments of different lengths L (100, 250, 100 μm) (not shown). A dielectric layer (200 nm of SiO2) was deposited on the sample surface and covered by a TiAu gate. The density variation with gate voltage was 1.1 × 1011 cm−2 V−1. The resistance in the presence of the perpendicular magnetic field R(B) has been measured in the temperature range 4.2–70 K using a standard four-point circuit with a 1–13 Hz ac current of 1–10 nA through the sample
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