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Many electron theory of 1/f Noise in doped semiconductors

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Many electron theory of 1/f Noise in doped semiconductors Alexander Burin Tulane University Motivation (Fundamental) Understanding the nature of anomalously strong ... – PowerPoint PPT presentation

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Title: Many electron theory of 1/f Noise in doped semiconductors


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Many electron theory of 1/f Noise in doped
semiconductors
Alexander Burin Tulane University
3
Motivation (Fundamental)
Understanding the nature of anomalously strong
1/f noise in hopping conduction (e. g. McCammon,
2000-2006 Savchenko, 2000-2003 (Si-P-B) G.
Deville, 2006, (Ga-As))
106
100
104
102
10
1
100
0.1
10-2
0.03
0.1
0.3
0.1
10
1
100
T (K)
? (Hz)
4
Motivation (Practical)
1/f-noise affects a performance of semiconductor
bolometers (McCammon, 2000-2006 Gershenson,
2000-2003 (Si-P))
Bolometers detect absorption of single X-ray or
cosmic particle and can measure its energy by
means of the change in temperature affecting the
semiconductor conductivity
5
Universal low temperature conductivity in doped
semiconductors (Shklovskii, Efros, 1978)
ln?
Universal strong temperature dependence serves to
define the small temperature variation induced by
X-ray absorption
T-1/2
6
1/f noise in operation regime T0.1K
Goal Develop the general theory to account for
the universal 1/f-noise
7
Previous work - 1
1. 1/f noise is caused by tunneling (McWorter,
(1957))
r/2
r
Hopping through intermediate sites breaks down
1/f transition rate statistics
8
Previous work - 2
2. 1/f noise is caused by tunneling from traps
(Shklovskii, (2003) Yu, (2003) Kozub (1996)
occasional configurations with no intermediate
sites)
E
E2
E1
Er
r
9
Previous work - 3
Trap noise, high T
10
Previous work - 4
Trap noise, low T
2e2/r
One charge with energy e2/r per volume r3 (Efros,
Shklovskii, 1975)
e2/r
r
11
Previous work - 5
Exponent reaches 1 for the variable-range hopping
rate
12
Problems of trap model
I
0.1
10
100
1
? (Hz)
13
Hypothesis Involvement of multi-electron
tunneling
  1. Simultaneous tunneling of multi-electron
    (N-electron) coupled clusters is characterized by
    tunneling amplitude V exp(-aN), ? leads to 1/f
    noise if transition rates
  2. Clusters can be formed due to long-range
    interaction (Burin, Kagan, 1995, 1996)
  3. We exploit the most straightforward case of
    random order, i. e. Wigner crystal like
    configuration formed statistically
  4. External noise source (atomic tunneling, etc.) is
    less probable because of the correlation of noise
    with metal-insulator transition

14
Chessboard cluster
r
15
Probability to form chessboard cluster of N sites
Structure close to that of the Wigners crystal
Site energy reproduces that of Wigners crystal
16
Transition of chessboard cluster tunneling
Tunneling
17
Transition of chessboard cluster thermal
activation
Thermal activation of domain boundary
18
Statistics of transition rates
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Statistics of transition rates - 2
Main contribution comes from the crossover regime
NNc
?
r
rc
20
Deviations from 1/f statistics
Practically unlimited applicability at low
temperature Tlt0.1e2/a
21
Conductivity noise
e2/T
22
Hooge constant, comparison with experiment
23
Results, for higher temperature, lower dimension
24
Conclusions
  1. Correlated transitions in coupled many-electron
    clusters account for the 1/f noise in a hopping
    conduction
  2. Clusters are made of ordered crystalline
    configurations formed due to fluctuations of a
    random potential

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Acknowledgements
Coworkers
Boris Shklovskii , special acknowledge for
supporting my life and work in UMN in the Fall
2005 (where this work has been done) during the
disaster in New Orleans
Veniamin Kozub
Yuri Galperin
Valery Vinokur
Funding
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