Transport properties of a two-dimensional electron liquid at high magnetic fields

Article

关键词: QUANTUM HALL STATES;    EDGE EXCITATIONS;    IMPURITY SCATTERING;    LUTTINGER LIQUID;    CHARGE;    MODEL;   

DOI  :  10.1103/PhysRevB.68.035314

来源: SCIE

【 摘 要 】

The chiral Luttinger liquid model for the edge dynamics of a two-dimensional electron gas in a strong magnetic field is derived from coarse-graining and a lowest Landau level projection procedure at arbitrary filling factors nu<1 -without reference to the quantum Hall effect. Based on this model, we develop a formalism to calculate the Landauer-Buttiker conductances in generic experimental setups including multiple leads and voltage probes. In the absence of tunneling between the edges the ideal Hall conductances (G(ij) =e(2) nu/h if lead j is immediately upstream of lead i, and G(ij)=0 otherwise) are recovered. Tunneling of quasiparticles of fractional charge e* between different edges is then included as an additional term in the Hamiltonian. In the limit of weak tunneling we obtain explicit expressions for the corrections to the ideal conductances. As an illustration of the formalism we compute the current- and temperature-dependent resistance R-xx(I,T) of a quantum point contact localized at the center of a gate-induced constriction in a quantum Hall bar. The exponent alpha in the low-current relation R-xx (I, 0)similar to I alpha-2 shows a nontrivial dependence on the strength of the inter-edge interaction, and its value changes as e*V-H, where V-H=hI/nu e(2) is the Hall voltage, falls below a characteristic crossover energy <(h)over bar>c/d, where c is the edge wave velocity and d is the length of the constriction. The consequences of this crossover are discussed vis-a-vis recent experiments in the weak tunneling regime.

【 授权许可】

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