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Electron phase coherence in mesoscop...

Trionfi, Aaron James.

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Electron phase coherence in mesoscopic normal metal wires.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Electron phase coherence in mesoscopic normal metal wires./
Author:	Trionfi, Aaron James.
Description:	108 p.
Notes:	Adviser: Douglas Natelson.
Contained By:	Dissertation Abstracts International68-03B.
Subject:	Physics, Condensed Matter. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3256752

Electron phase coherence in mesoscopic normal metal wires.
Trionfi, Aaron James.

Electron phase coherence in mesoscopic normal metal wires. - 108 p.

Adviser: Douglas Natelson.

Thesis (Ph.D.)--Rice University, 2007.

Corrections to the classically predicted electrical conductivity in normal metals arise due to the quantum mechanical properties of the conduction electrons. These corrections provide multiple experimental tests of the conduction electrons' quantum phase coherence. I consider if independent measurements of the phase coherence via different corrections are quantitatively consistent, particularly in systems with spin-orbit or magnetic impurity scattering. More precisely, do independent quantum corrections to the classically predicted conductivity depend identically on the ubiquitous dephasing mechanisms in normal metals? I have inferred the coherence lengths from the weak localization magnetoresistance, magnetic field-dependence of time-dependent universal conductance fluctuations, and magnetic field-dependent universal conductance fluctuations, three observable quantum corrections, in quasi one- and two-dimensional AuPd wires and quasi-1D Ag and Au wires between 2 and 20 K. While the coherence lengths inferred from weak localization and time-dependent universal conductance fluctuations are in excellent quantitative agreement in AuPd, the strong quantitative agreement is apparently lost below a critical temperature in both Ag and Au. Such a disagreement is inconsistent with current theory and must be explained. I developed a hypothesis attributing the coherence length discrepancy seen in Ag and Au to a crossover from the saturated to unsaturated time-dependent conductance fluctuation regime. Two experimental tests were then employed to test this hypothesis. One test examined the effects of a changing spin-flip scattering rate in Au while the second examined how passivation of the two level systems responsible for time-dependent conductance fluctuations at the surface of a Au nanowire affects the inferred coherence lengths. The results of the two tests strongly indicate that the observed disagreement in Au (and likely Ag) is indeed due to a crossover from saturated to unsaturated time-dependent conductance fluctuations.Subjects--Topical Terms:

1018743
Physics, Condensed Matter.

Electron phase coherence in mesoscopic normal metal wires.
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005 20110630
008 110630s2007 ||||||||||||||||| ||eng d
035 $a (UMI)AAI3256752
035 $a AAI3256752
040 $a UMI $c UMI
100 1 $a Trionfi, Aaron James. $3 1280952
245 1 0 $a Electron phase coherence in mesoscopic normal metal wires.
300 $a 108 p.
500 $a Adviser: Douglas Natelson.
500 $a Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1693.
502 $a Thesis (Ph.D.)--Rice University, 2007.
520 $a Corrections to the classically predicted electrical conductivity in normal metals arise due to the quantum mechanical properties of the conduction electrons. These corrections provide multiple experimental tests of the conduction electrons' quantum phase coherence. I consider if independent measurements of the phase coherence via different corrections are quantitatively consistent, particularly in systems with spin-orbit or magnetic impurity scattering. More precisely, do independent quantum corrections to the classically predicted conductivity depend identically on the ubiquitous dephasing mechanisms in normal metals? I have inferred the coherence lengths from the weak localization magnetoresistance, magnetic field-dependence of time-dependent universal conductance fluctuations, and magnetic field-dependent universal conductance fluctuations, three observable quantum corrections, in quasi one- and two-dimensional AuPd wires and quasi-1D Ag and Au wires between 2 and 20 K. While the coherence lengths inferred from weak localization and time-dependent universal conductance fluctuations are in excellent quantitative agreement in AuPd, the strong quantitative agreement is apparently lost below a critical temperature in both Ag and Au. Such a disagreement is inconsistent with current theory and must be explained. I developed a hypothesis attributing the coherence length discrepancy seen in Ag and Au to a crossover from the saturated to unsaturated time-dependent conductance fluctuation regime. Two experimental tests were then employed to test this hypothesis. One test examined the effects of a changing spin-flip scattering rate in Au while the second examined how passivation of the two level systems responsible for time-dependent conductance fluctuations at the surface of a Au nanowire affects the inferred coherence lengths. The results of the two tests strongly indicate that the observed disagreement in Au (and likely Ag) is indeed due to a crossover from saturated to unsaturated time-dependent conductance fluctuations.
590 $a School code: 0187.
650 4 $a Physics, Condensed Matter. $3 1018743
650 4 $a Physics, Electricity and Magnetism. $3 1019535
690 $a 0607
690 $a 0611
710 2 $a Rice University. $3 960124
773 0 $t Dissertation Abstracts International $g 68-03B.
790 $a 0187
790 1 0 $a Natelson, Douglas, $e advisor
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3256752