Landolt-Börnstein - Group III Condensed Matter

1.3 Description of the experimental observations


This chapter presents a description of experimental observations on quantum corrections to metallic conductivity, Aharonov-Bohm (AB) oscillations of magneto-resistance, conductance fluctuations, the quantum Hall effect, resistance quantization in mesoscopic point contacts, conductance oscillations in quantum dots and persistent currents in non-superconducting rings, under survey of mesoscopic quantum transport. Interaction between the electrons leads to characteristic corrections to the low temperature behaviour of the resistance. Weak-localization effects are distinguished by magnetoresistance measurements, since in the case of interactions a positive magnetoresistance is observed. The phenomenon of AB-oscillations, resulting from weak-localization corrections, of the magnetoconductance of small metallic cylinders has been predicted. The first observation was made on metal-oxide-silicon field-effect transistor (MOSFET) accumulation layer samples. Hall resistance was determined by measuring the Hall voltage UH between probes on opposite sides. The Hall resistance and longitudinal resistance were determined as functions of a magnetic field for fixed electron density, mobility as a function of a filling factor. Two split gates in series have been fabricated on top of a AlGaAs/GaAs-heterostructure, and an additional backgate on the rear of the sample, in order to control the electron density independently of the point contacts formed by a voltage at the split gates. The conductance through electron island, when measured at mK-temperatures as a function of the voltage applied to the back-gate, exhibits resonance-like peaks which are at periodic in gate voltage.

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1.3 Description of the experimental observations
Book Title
Electronic Transport. Part 1: Quantum Point Contacts and Quantum Wires
1 Survey of mesoscopic quantum transport
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Landolt-Börnstein - Group III Condensed Matter
  • B. Kramer
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  • B. Kramer
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