EXPERIMENTAL STUDIES OF QUANTUM MECHANICAL INTERFERENCE EFFECTS IN MAGNETORESISTANCE OF SINGLE CRYSTALS OF ULTRAPURE MAGNESIUM

Persistent Link:
http://hdl.handle.net/10150/281898
Title:
EXPERIMENTAL STUDIES OF QUANTUM MECHANICAL INTERFERENCE EFFECTS IN MAGNETORESISTANCE OF SINGLE CRYSTALS OF ULTRAPURE MAGNESIUM
Author:
Sandesara, Niranjan Bhogilal
Issue Date:
1980
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
New types of quantum interference oscillations in transverse magnetoresistance of single crystals of ultrapure magnesium are reported. These oscillations occur as a function of the angle of rotation when the current is passed along the [112̄0] direction and the magnetic field H(→) is rotated by ≲ 1° from [101̄0] towards the [0001] symmetry axis. In order to characterize the oscillations, extensive qualitative data were taken for fields up to 24 kG and for temperatures in the range of 1.4 K-4.2 K. It is shown that these angle-dependent oscillations have the same origin as the field-dependent interferometer oscillations first reported by Stark and Friedberg. Both types of oscillations arise from the electron quantum states on the coupled orbit network, which is obtained for H(→)∥[1010]. It is shown that high sensitivity of the oscillations and the background magnetoresistance (for H within →1° from [101̄0] to field inhomogeneity and crystal strain yields strong evidence for a new regime of quantum transport. In this regime, quantum phase coherence of the electrons extends over distances of the order of 0.1 mm, and coherence determines not only the oscillation amplitudes but also the background. The "stacked mirror" model of Stark and Reifenberger is not applicable in such a regime of transport. A rudimentary model is presented that seems to be in qualitative agreement with the data. However, band structure calculations firmly establish that the large oscillations arise from the symmetry breaking of the two interferometer lobes as the field is rotated away from [101̄0].
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Magnetoresistance.; Magnesium -- Magnetic properties.; Magnesium crystals.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Physics
Degree Grantor:
University of Arizona
Advisor:
Stark, Royal W.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleEXPERIMENTAL STUDIES OF QUANTUM MECHANICAL INTERFERENCE EFFECTS IN MAGNETORESISTANCE OF SINGLE CRYSTALS OF ULTRAPURE MAGNESIUMen_US
dc.creatorSandesara, Niranjan Bhogilalen_US
dc.contributor.authorSandesara, Niranjan Bhogilalen_US
dc.date.issued1980en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractNew types of quantum interference oscillations in transverse magnetoresistance of single crystals of ultrapure magnesium are reported. These oscillations occur as a function of the angle of rotation when the current is passed along the [112̄0] direction and the magnetic field H(→) is rotated by ≲ 1° from [101̄0] towards the [0001] symmetry axis. In order to characterize the oscillations, extensive qualitative data were taken for fields up to 24 kG and for temperatures in the range of 1.4 K-4.2 K. It is shown that these angle-dependent oscillations have the same origin as the field-dependent interferometer oscillations first reported by Stark and Friedberg. Both types of oscillations arise from the electron quantum states on the coupled orbit network, which is obtained for H(→)∥[1010]. It is shown that high sensitivity of the oscillations and the background magnetoresistance (for H within →1° from [101̄0] to field inhomogeneity and crystal strain yields strong evidence for a new regime of quantum transport. In this regime, quantum phase coherence of the electrons extends over distances of the order of 0.1 mm, and coherence determines not only the oscillation amplitudes but also the background. The "stacked mirror" model of Stark and Reifenberger is not applicable in such a regime of transport. A rudimentary model is presented that seems to be in qualitative agreement with the data. However, band structure calculations firmly establish that the large oscillations arise from the symmetry breaking of the two interferometer lobes as the field is rotated away from [101̄0].en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectMagnetoresistance.en_US
dc.subjectMagnesium -- Magnetic properties.en_US
dc.subjectMagnesium crystals.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorStark, Royal W.en_US
dc.identifier.proquest8107441en_US
dc.identifier.oclc8139830en_US
dc.identifier.bibrecord.b13688169en_US
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