Post on 31-Dec-2015
description
Nonequilibrium phenomena in two-dimensional electron Corbino rings at large filling factors
A.A. Bykov, I.S. Strygin, D.V. Dmitriev
Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Science, 630090 Novosibirsk, Russia
S. Dietrich, S.A. Vitkalov
Physics Department, City College of the City University of New York, New York 10031, USA
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APPLIED PHYSICS LETTERS 100, 251602 (2012)
PHYSICAL REVIEW B 87, 081409(R) (2013)
1. Hall-bar and Corbino-disk
2. 2D system at large filling factors
3. Zener tunneling between Landau orbits and Zero-differential resistance in Hall bars
4. Samples and experiment
5. Zener tunneling between Landau orbits in two-dimensional electron Corbino rings
6. Zero-differential conductance of two-dimensional electrons in crossed electric and magnetic fields
7. Summary
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W
L
32
1 4
56
2rout
2rin
1
2
Hall-bar Corbino-disk
xx = (V23 /I14)(W/L) = (V65 /I14)(W/L)
xy = V26 /I14 = V35 /I14 xx = (I12/2V12)ln(rout/rin)
σ̂ = 1/ ρ̂ xx = xx /(xx
2 + xy2)
xy = xy /(xx
2 + xy2)
xx = xx /(xx2 + xy
2)
xy = xy /(xx2 + xy
2)
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D. C. Tsui, H. L. Stormer, A. C. Gossard. PRL 48, 1559 (1982).
K. v Klitzing, G. Dorda, M. Pepper. PRL 45, 494 (1980).
Quantum Hall Effect
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B = 0 B > 0
g ()
EF fT
g() = g0[1-2cos(2/c)]
g0 = m*/2
= exp(-/cq)
fT = 1/{exp[( - EF )/kBT] +1}
0 g0 E1
/q > c
B > 0
g = g0<< c > c
2D systems at large filling factors
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I. A. Dmitriev, A.D. Mirlin, D. G. Polyakov, M. A. Zudov REV. MOD. PHYS. 84 (2012)
Nonlinear magnetotransport in Hall bar
Rxx
= Vdc
/Idc
rxx
= Vac
/Iac
~ Iac
Idc V
dc, V
ac
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R = 2Rc
kF
R = 2Rc
2RceEH = lc
N
N+1
N+2
C
F = - eEH
Эне
ргия
эле
ктро
на
RN
c RN+1
c
Координата центра электронной орбиты
k = 2kF
kF
EF
Zener tunneling between Landau orbits
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Zener tunneling between Landau orbits in Hall bar
C. L. Yang, J. Zhang, R. R. Du, J. A. Simmons, J. L. Reno. PRL 89, 076801 (2002).
2RceEH = lc
kF = 2kF
“HIRO”
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-20 0 20
0
100r
xx ()
Idc
(A)
B = 0.8 T
0.0 0.2 0.4 0.6 0.8 1.0
-50
0
50
100
150
Idc
= 4 A
Idc
= 8.4 A
Idc
= 20 A
r xx
()
B (T)
T = 2.1 K
Zero-Differential Resistance State of Two-Dimensional Electron Systems in Strong Magnetic Fields
A. A. Bykov, J-Q. Zhang, S, Vitkalov, A. Kalagin, A. Bakarov, PRL 99, 116801 (2007). UIWSPS-2014 11
Heterostructure GaAs/AlAs
n ~ 81015 м-2
~ 200 м2/Вс
T = 1.6 - 4.2 K B < 2 T
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Magnetic field dependencies of the conductance of "narrow" and "wide" 2D electronCorbino discs
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Zener tunneling between Landau orbits in Corbino rings
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Zener tunneling between Landau orbits in Corbino rings
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Zero-differential conductance of two-dimensional electrons in crossed electric and magnetic fields
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Current induced oscillations of differential conductivity of two-dimension electrons, placed in quantizing magnetic fields, are observed in GaAs quantum wells in Corbino geometry.
The oscillations are periodic in the square of the inverse magnetic field and occur in Corbino rings with a width which is much lesser than the radius of the rings.
The conductance oscillations are described by Zener tunneling between Landau orbits in the absence of the Hall electric field.
An electronic state with zero-differential conductance is found in nonlinear response to an electric field E applied to two dimensional Corbino discs of highly mobile carriers placed in quantizing magnetic fields.
The state occurs above a critical electric fieldE > Eth at low temperatures and is accompanied by an abrupt dip in the differential conductance.
Summary
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