Rights statement: © 1997 The American Physical Society
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Quantum versus semiclassical analysis of the conductivity of two-dimensional electrons in a magnetic field
AU - Hayne, M
AU - Usher, Alan
AU - Harris, Jeffery J
AU - Foxon, C Tom
N1 - © 1997 The American Physical Society
PY - 1997/10/15
Y1 - 1997/10/15
N2 - We present experimental evidence for the levitation of extended slates of a two-dimensional electron system in a magnetic field, and establish the presence of alternating regions of localized and extended states in the density of states to Landau-level filling factors (nu) as high as 80. Monitoring the Hall voltage of a modulation-doped GaAs/AlxGa1-xAs heterojunction at fixed magnetic field during continuous illumination from light-emitting diodes reveals a steplike structure with plateaus at even integer nu between 22 and 80 at a temperature of 0.3 K. We derive a general expression for the conductivity due to rectangular bands of extended states, and show that the observed temperature dependence of the Shubnikov-de Haas oscillations is consistent with this picture. An analysis of the oscillations using this expression reveals the predicted levitation of the extended states.
AB - We present experimental evidence for the levitation of extended slates of a two-dimensional electron system in a magnetic field, and establish the presence of alternating regions of localized and extended states in the density of states to Landau-level filling factors (nu) as high as 80. Monitoring the Hall voltage of a modulation-doped GaAs/AlxGa1-xAs heterojunction at fixed magnetic field during continuous illumination from light-emitting diodes reveals a steplike structure with plateaus at even integer nu between 22 and 80 at a temperature of 0.3 K. We derive a general expression for the conductivity due to rectangular bands of extended states, and show that the observed temperature dependence of the Shubnikov-de Haas oscillations is consistent with this picture. An analysis of the oscillations using this expression reveals the predicted levitation of the extended states.
KW - FERMION EFFECTIVE-MASS
KW - 2-DIMENSIONAL ELECTRONS
KW - TRANSPORT-COEFFICIENTS
KW - COMPOSITE FERMIONS
KW - DELOCALIZED STATES
KW - LANDAU-LEVELS
KW - HALL REGIME
KW - ENHANCEMENT
KW - OSCILLATIONS
KW - LEVITATION
U2 - 10.1103/PhysRevB.56.10446
DO - 10.1103/PhysRevB.56.10446
M3 - Journal article
VL - 56
SP - 10446
EP - 10452
JO - Physical review B
JF - Physical review B
SN - 1550-235X
IS - 16
ER -