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Charge imbalance and bilayer two-dimensional electron systems at ν_T=1

Champagne, A. R. and Finck, A. D. K. and Eisenstein, J. P. and Pfeiffer, L. N. and West, K. W. (2008) Charge imbalance and bilayer two-dimensional electron systems at ν_T=1. Physical Review B, 78 (20). Art. No. 205310. ISSN 1098-0121. http://resolver.caltech.edu/CaltechAUTHORS:CHAprb08

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Abstract

We use interlayer tunneling to study bilayer two-dimensional electron systems at ν_T=1 over a wide range of charge-density imbalance Δν=ν_1−ν_2 between the two layers. We find that the strongly enhanced tunneling associated with the coherent excitonic ν_T=1 phase at small layer separation can survive at least up to an imbalance of Δν=0.5, i.e., (ν_1,ν_2)=(3/4,1/4). Phase transitions between the excitonic ν_T=1 state and bilayer states which lack significant interlayer correlations can be induced in three different ways: by increasing the effective interlayer spacing d/ℓ, the temperature T, or the charge imbalance Δν. We observe that close to the phase boundary the coherent ν_T=1 phase can be absent at Δν=0, present at intermediate Δν, and then absent again at large Δν, thus indicating an intricate phase competition between it and incoherent quasi-independent layer states. At zero imbalance, the critical d/ℓ shifts linearly with temperature, while at Δν=1/3 the critical d/ℓ is only weakly dependent on T. At Δν=1/3 we report on an observation of a direct phase transition between the coherent excitonic ν_T=1bilayer integer quantum Hall phase and the pair of single-layer fractional quantized Hall states at ν_1=2/3 and ν_2=1/3.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevB.78.205310DOIArticle
https://arxiv.org/abs/0808.1257arXivDiscussion Paper
Additional Information:© 2008 The American Physical Society. (Received 8 August 2008; published 10 November 2008) We are grateful to S. Das Sarma, A.H. MacDonald, E.H. Rezayi, X.G. Wen, K. Yang, and especially to G. Refael for discussions and to I.B. Spielman for technical help. This work was supported by the NSF under Grant No. DMR-0552270 and the DOE under Grant No. DE-FG03-99ER45766.
Funders:
Funding AgencyGrant Number
NSFDMR-0552270
Department of Energy (DOE)DE-FG03-99ER45766
Subject Keywords:aluminum compounds; charge density waves; excitons; gallium arsenide; gallium compounds; III-V semiconductors; semiconductor heterojunctions; semiconductor quantum wells; tunnelling
Record Number:CaltechAUTHORS:CHAprb08
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:CHAprb08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12391
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:15 Nov 2008 01:02
Last Modified:28 May 2019 16:34

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