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Browsing by Author "Rudolph, M."

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    Electronic and quantum phase coherence properties of bismuth thin films
    Rudolph, M.; Heremans, Jean J. (AIP Publishing, 2012-06)
    We present a method to deposit bulk-like Bi films by thermal evaporation and study the electrical, quantum coherence, and physical properties. A two stage growth procedure was found to optimize the film properties, with an initial wetting layer deposited at lower temperature followed by an active layer at higher temperature. Transport measurements indicate carrier properties comparable to molecular beam epitaxial films and display weak-antilocalization, from which the quantum phase coherence lengths are deduced. A 76 nm film is found to optimally exhibit both bulk-like Bi characteristics and the 2-dimensional quantum coherence properties desired for Bi-based quantum devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729035]
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    Spin-orbit interaction and phase coherence in lithographically defined bismuth wires
    Rudolph, M.; Heremans, Jean J. (American Physical Society, 2011-05-18)
    We present low-temperature magnetoresistance measurements on lithographically defined bismuth wires. The phase-coherence time and the spin-orbit scattering time are obtained by analysis of weak antilocalization, with values for the phase-coherence time supported by analysis of the universal conductance fluctuations present in the wires. We find that the phase-coherence time is dominated by electron-phonon scattering above approximate to 2 K and saturates below that temperature, with saturation delayed to a lower temperature in wider wires. The spin-orbit scattering time shows a weak temperature dependence above 2 K, and also shows a dependence on wire width. The spin-orbit scattering time increases as the width is reduced, as is also observed in wires fabricated from spin-orbit coupled two-dimensional systems in semiconductor heterostructures. The similarity is discussed in light of weak antilocalization in the two-dimensional strongly spin-orbit coupled Bi(001) surface states.