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Microwave conductivity of magnetic f...

Princeton University.

Microwave conductivity of magnetic field induced insulating phase of bilayer hole systems.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Microwave conductivity of magnetic field induced insulating phase of bilayer hole systems.
Author:	Wang, Zhihai.
Description:	90 p.
Notes:	Adviser: Daniel C. Tsui.
Notes:	Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1694.
Contained By:	Dissertation Abstracts International68-03B.
Subject:	Physics, Condensed Matter.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3255832

Microwave conductivity of magnetic field induced insulating phase of bilayer hole systems.
Wang, Zhihai.

Microwave conductivity of magnetic field induced insulating phase of bilayer hole systems. - 90 p.

Adviser: Daniel C. Tsui.

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

This thesis presents studies of the magnetic field induced insulating phase of bilayer hole systems. This insulating phase terminates the quantum Hall state series at sufficiently small total Landau filling factor nu, and is understood as bilayer Wigner crystal (BWC), for samples of sufficiently low disorder. For a Wigner crystal in real samples, bilayer or single layer, the disorder not only gives the insulating behavior but also produces a striking microwave or rf conductivity resonance, or pinning mode, which is a collective oscillation of the carriers about their pinned positions. Pinning mode resonances of single layers have been studied experimentally and theoretically and have proven to be valuable for obtaining information about the single layer, pinned Wigner solids. As will be presented in this thesis, for BWC, the pinning modes exhibits features which depend sensitively on magnetic field, interlayer separation d, and bilayer densities.Subjects--Topical Terms:

226939
Physics, Condensed Matter.

Microwave conductivity of magnetic field induced insulating phase of bilayer hole systems.
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100 0 $a Wang, Zhihai. $3 264362
245 1 0 $a Microwave conductivity of magnetic field induced insulating phase of bilayer hole systems.
300 $a 90 p.
500 $a Adviser: Daniel C. Tsui.
500 $a Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1694.
502 $a Thesis (Ph.D.)--Princeton University, 2007.
520 # $a This thesis presents studies of the magnetic field induced insulating phase of bilayer hole systems. This insulating phase terminates the quantum Hall state series at sufficiently small total Landau filling factor nu, and is understood as bilayer Wigner crystal (BWC), for samples of sufficiently low disorder. For a Wigner crystal in real samples, bilayer or single layer, the disorder not only gives the insulating behavior but also produces a striking microwave or rf conductivity resonance, or pinning mode, which is a collective oscillation of the carriers about their pinned positions. Pinning mode resonances of single layers have been studied experimentally and theoretically and have proven to be valuable for obtaining information about the single layer, pinned Wigner solids. As will be presented in this thesis, for BWC, the pinning modes exhibits features which depend sensitively on magnetic field, interlayer separation d, and bilayer densities.
520 # $a We also studied the pinning modes of BWC in imbalanced bilayer states. Under a considerable range of imbalance, the enhanced pinning seen in the balanced state persists, while the resonance broadens as imbalance is increased. For a sufficiently large imbalance, this enhanced pinning disappears abruptly. At this point, the resonance line width has a distinct maximum. We interpret these results as due to changes in the pseudospin magnetic ordering, driven by density imbalance.
520 # $a We start from the balanced case, in which the two layers have equal carrier densities. Bilayer effects were studied by comparing the spectra of such balanced states to those of single layers realized in situ by depleting one of the layers. The BWC experiences an enhanced pinning (compared with the pinning of single layer Wigner crystals), only for small enough d. We interpreted this enhanced pinning as due to a quantum interlayer correlation, in which the BWC has carrier wave functions that spread coherently and equally between the two layers, and thus each carrier is affected by the disorder of the two layers. The BWC like this would be an easy-plane pseudospin ferromagnet, with pseudospin specifying the layers. Our balanced state studies also show that, only for sufficiently small d, development of the resonance shows features around nu = 1/2 or 2/3, demonstrating the effect, within the low nu BWC insulator, of correlations present in the fractional quantum Hall states.
590 $a School code: 0181.
650 # 0 $a Physics, Condensed Matter. $3 226939
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710 0 # $a Princeton University. $3 212488
773 0 # $g 68-03B. $t Dissertation Abstracts International
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790 1 0 $a Tsui, Daniel C., $e advisor
791 $a Ph.D.
792 $a 2007
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