Insulating states of a broken-gap two-dimensional electron-hole system

Kei Takashina, Robin J Nicholas, Beata Kardynal, Nigel J Mason, Duncan K Maude, Jean Claude Portal

Research output: Contribution to journalArticle

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Abstract

It has recently been found that an InAs/GaSb based electron-hole system exhibits insulating behavior with unusual properties when the numbers of occupied electron and hole Landau levels are equal [R. J. Nicholas, K. Takashina, M. Lakrimi, B. Kardynal, S. Khym, N. J. Mason, D. M. Symons, D. K. Maude, and J. C. Portal, Phys. Rev. Lett. 85, 2364 (2000)]. In this insulating state, the Hall resistance becomes symmetric (even) under field reversal [Rxy(B)=Rxy(-B)], and both the Hall and longitudinal resistances display reproducible fluctuations. In this paper we present experimental studies of the geometry dependence of this phenomenon. In particular, we show conclusively that the conduction responsible for the reproducible fluctuations and the symmetric Hall resistance occur due to the presence of the mesa edge. Further investigations of the edge conductance are presented. We show that as a function of magnetic field, the edge conduction shows a qualitatively opposite behavior to the conductivity in the sample interior. This is confirmed through measurements with an in-plane component of magnetic field. Also, the size of the conductance fluctuations is found to have a monotonic relationship with the absolute value of the conductance. A model based on counterpropagating edge channels is presented which qualitatively accounts for the observed behavior.
Original languageEnglish
Article number235303
Number of pages10
JournalPhysical Review B
Volume68
Issue number23
DOIs
Publication statusPublished - 5 Dec 2003

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Hall resistance
Magnetic fields
Electrons
conduction
Geometry
mesas
magnetic fields
conductivity
geometry
electrons
indium arsenide

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Takashina, K., Nicholas, R. J., Kardynal, B., Mason, N. J., Maude, D. K., & Portal, J. C. (2003). Insulating states of a broken-gap two-dimensional electron-hole system. Physical Review B, 68(23), [235303]. https://doi.org/10.1103/PhysRevB.68.235303

Insulating states of a broken-gap two-dimensional electron-hole system. / Takashina, Kei; Nicholas, Robin J; Kardynal, Beata; Mason, Nigel J; Maude, Duncan K; Portal, Jean Claude.

In: Physical Review B, Vol. 68, No. 23, 235303, 05.12.2003.

Research output: Contribution to journalArticle

Takashina, K, Nicholas, RJ, Kardynal, B, Mason, NJ, Maude, DK & Portal, JC 2003, 'Insulating states of a broken-gap two-dimensional electron-hole system', Physical Review B, vol. 68, no. 23, 235303. https://doi.org/10.1103/PhysRevB.68.235303
Takashina, Kei ; Nicholas, Robin J ; Kardynal, Beata ; Mason, Nigel J ; Maude, Duncan K ; Portal, Jean Claude. / Insulating states of a broken-gap two-dimensional electron-hole system. In: Physical Review B. 2003 ; Vol. 68, No. 23.
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