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Weak Localization (weak + localization)
Selected AbstractsWeak localization and the Mooij rule in disordered metalsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003Mi-Ae Park Abstract Weak localization leads to the same correction to both the conductivity and the McMillan's electron,phonon coupling constant , (and ,tr, transport electron,phonon coupling constant). Consequently the temperature dependence of the thermal electrical resistivity is decreasing as the conductivity is decreasing due to weak localization, which results in the decrease of the temperature coefficient of resistivity (TCR) with increasing the residual resistivity. When , and ,tr are approaching zero, only the residual resistivity part remains and it gives rise to the negative TCR. Accordingly, the Mooij rule is a manifestation of weak localization correction to the conductivity and the electron,phonon interaction. This understanding provides a new means of probing the phonon-mechanism in exotic superconductors and an opportunity of fabricating new novel devices. [source] Effect of heat treatment on various physical properties in Zr80Ni20 metallic glassPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2006I. Kokanovi Abstract The effect of heat treatment on various physical properties in Zr80Ni20 metallic glass has been investigated by means of differential scanning calorimetry and electrical resistivity measurements. Experimental values for the crystallisation temperature and activation energy of the crystallisation processes were derived by studying these processes at different heating rates. The electrical resistivity of the annealed samples up to a temperature slightly above the first crystallization exotherm decreases with decreasing heating rates and increasing annealing temperatures. The temperature dependence of the electrical resistivity of the samples has been interpreted in terms of the weak localization of electrons and contribution by electron,phonon scattering. The contribution by electron,phonon scattering increases with increasing the fraction of crystalline phases in the glass matrix. The superconducting transition temperature, Tc, of the Zr80Ni20 metallic glass annealed at heating rates of 60 K/min and 10 K/min up to annealing temperatures below its second crystallisation exotherm decreases with decreasing heating rates and increasing annealing temperatures. The homogeneity of the annealed Zr80Ni20 metallic glass is discussed by using the superconducting transition width as a criterion. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electron localization and emission mechanism in wurtzite (Al, In, Ga)N alloysPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2010Qihang Liu Abstract The electronic structures of wurtzite InGaN and AlGaN alloys are investigated using the first-principle density functional theory calculation. The results indicate that some short In,N,In atomic chains and small In,N atomic condensates composed of a few In and N atoms can be randomly formed in InGaN alloys. The electrons at the top of valence bands can be effectively localized in the vicinity of the In,N,In zigzag chains (weak localization) and the In,N atomic condensates (strong localization). These localized electrons extremely enhance the emission efficiency of InGaN alloys. [source] Aharonov,Bohm effects in multiwall carbon nanotubesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 13 2006C. Strunk Abstract We investigate quantum transport phenomena in multiwall carbon nanotubes in perpendicular and parallel magnetic field. An efficient gating technique allows for a considerable tuning of the nanotube doping level. We show that the weak localization is strongly suppressed at peaks at certain gate voltages which can be linked with the bottoms of one-dimensional electronic subbands. In large parallel magnetic field, we observe a superposition of h /2e -periodic Altshuler-Aronov-Spivak oscillations and an additional h /e -periodic contribution, which we attribute to the magnetic field dependence of the band structure. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Quantum transport in high mobility AlGaN/GaN 2DEGs and nanostructuresPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 7 2006S. Schmult Abstract High mobility two-dimensional electron systems in GaN/AlGaN heterostructures have been realized by plasma assisted molecular beam epitaxy on GaN templates. In the density range of 1011 cm,2 to 1012 cm,2, mobility values exceeding 160000 cm2/Vs have been achieved. Scattering mechanisms that presently limit the production of higher mobility samples are discussed. We present results of a systematic study of the weak localization and antilocalization corrections to the classical conductivity at very low magnetic fields. The unambiguous observation of a conductivity maximum at B = 0 suggests that spin,orbit scattering is not negligible in GaN heterostructures as one might expect for a wide-bandgap system. We have recently realized electron transport through GaN nanostructures. We report on the transport properties of the first quantum point contacts (QPCs) in GaN. These devices are used to study one-dimensional transport in the Nitride system. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Weak localization and the Mooij rule in disordered metalsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003Mi-Ae Park Abstract Weak localization leads to the same correction to both the conductivity and the McMillan's electron,phonon coupling constant , (and ,tr, transport electron,phonon coupling constant). Consequently the temperature dependence of the thermal electrical resistivity is decreasing as the conductivity is decreasing due to weak localization, which results in the decrease of the temperature coefficient of resistivity (TCR) with increasing the residual resistivity. When , and ,tr are approaching zero, only the residual resistivity part remains and it gives rise to the negative TCR. Accordingly, the Mooij rule is a manifestation of weak localization correction to the conductivity and the electron,phonon interaction. This understanding provides a new means of probing the phonon-mechanism in exotic superconductors and an opportunity of fabricating new novel devices. [source] | ||||||||||