Measurement of diffusion thermopower in the quantum Hall systems

Abstract

We have measured diffusion thermopower in a two-dimensional electron gas at low temperature ($T$=40 mK) in the field range 0 $<B<$ 3.4 T, by employing the current heating technique. A Hall bar device is designed for this purpose, which contains two crossing Hall bars, one for the measurement and the other used as a heater, and is equipped with a metallic front gate to control the resistivity of the areas to be heated. In the low magnetic field regime ($B\le$ 1 T), we obtain the transverse thermopower $S_{yx}$ that quantitatively agrees with the $S_{yx}$ calculated from resistivities using the generalized Mott formula. In the quantum Hall regime ($B\ge$ 1T), we find that $S_{yx}$ signal appears only when both the measured and the heater area are in the resistive (inter-quantum Hall transition) region. Anomalous gate-voltage dependence is observed above $\sim$1.8 T, where spin-splitting in the measured area becomes apparent.

4 pages, 4 figures, EP2DS-18

References in corpus (3)

• Observation of Chiral Heat Transport in the Quantum Hall Regime
• Thermopower as a Possible Probe of Non-Abelian Quasiparticle Statistics in Fractional Quantum Hall Liquids
• Highly enhanced thermopower in two-dimensional electron systems at milliKelvin temperatures

Cited by in corpus (3)

• Diffusion Thermopower of Quantum Hall States Measured in Corbino Geometry
• Anisotropic Behavior of the Thermoelectric Power and the Thermal Conductivity in a Unidirectional Lateral Superlattice: A Typical Anisotropic System Exhibiting Two Distinct Nernst Coefficients
• Current-induced cooling phenomenon in a two-dimensional electron gas under a magnetic field