Juhn-Jong Lin

Recent experimental studies of electron dephasing in metal and semiconductor mesoscopic structures

In this review, we discuss the results of recent experimental studies of the low-temperature electron dephasing time (τφ) in metal and semiconductor mesoscopic structures. A major focus of this review is on the use of weak localization, and other quantum-interference-related phenomena, to determine the value of τφ in systems of different dimensionality and with different levels of disorder. Significant attention is devoted to a discussion of three-dimensional metal films, in which dephasing is found to predominantly arise from the influence of electron–phonon (e–ph) scattering. Both the temperature and electron mean free path dependences of τφ that result from this scattering mechanism are found to be sensitive to the microscopic quality and degree of disorder in the sample. The results of these studies are compared with the predictions of recent theories for the e–ph interaction. We conclude that, in spite of progress in the theory for this scattering mechanism, our understanding of the e–ph interaction remains incomplete. We also discuss the origins of decoherence in low-diffusivity metal films, close to the metal–insulator transition, in which evidence for a crossover of the inelastic scattering, from e–ph to ‘critical’ electron–electron (e–e) scattering, is observed. Electron– electron scattering is also found to be the dominant source of dephasing in experimental studies of semiconductor quantum wires, in which the effects of both large- and small-energy-transfer scattering must be taken into account. The latter, Nyquist, mechanism is the stronger effect at a few kelvins, and may be viewed as arising from fluctuations in the electromagnetic background, generated by the thermal motion of electrons. At higher temperatures, however, a crossover to inelastic e–e scattering typically occurs; and evidence for this large-energy-transfer process has been found at temperatures as high as 30 K. Electron–electron interactions are also thought to play an important role in dephasing in ballistic quantum dots, and the results of recent experiments in this area are reviewed. A common feature of experiments, in both dirty metals 3 Authors to whom any correspondence should be addressed.

Electrical resistivities and thermopowers of transparent Sn-doped indium oxide films

We have systematically measured the electrical resistivities and thermopowers of transparent tin-doped indium oxide films. We found that the resistivities obey the Bloch-Gruneisen law between 25 and 300K, whereas below 25K, the resistivities slightly increase logarithmically with the decreasing temperature due to the weak-localization and electron-electron interaction effects. The thermopowers are negative and decrease linearly with temperature from 300K down to 1.8K. Our results strongly indicate that the tin-doped indium oxide films behave as a good, free-electron-like conductor while being transparent.

Weak antilocalization in topological insulator Bi2Te3 microflakes

We have studied the carrier transport in two topological insulator (TI) Bi

Variable-range-hopping conduction processes in oxygen deficient polycrystalline ZnO films

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Electrical conduction processes in ZnO in a wide temperature range 20–500 K

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Electrical conduction mechanisms in natively doped ZnO nanowires (II)

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Four-probe electrical-transport measurements on single indium tin oxide nanowires between 1.5?and?300?K

microflakes between 0.3 and 10 K and under applied backgate voltages (

Growth of single-crystalline RuO2 nanowires with one- and two-nanocontact electrical characterizations

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Contact to ZnO and intrinsic resistances of individual ZnO nanowires with a circular cross section

). Logarithmic temperature dependent resistance corrections due to the two-dimensional electron-electron interaction effect in the presence of weak disorder were observed. The extracted Coulomb screening parameter is negative, which is in accord with the situation of strong spin-orbit scattering as is inherited in the TI materials. In particular, positive magnetoresistances (MRs) in the two-dimensional weak-antilocalization (WAL) effect were measured in low magnetic fields, which can be satisfactorily described by a multichannel-conduction model. Both at low temperatures of

Disorder Dependence of Electron-Phonon Scattering Time in Bulk Ti1-xAlx Alloys

T < 1