Role of the Andreev current in bolometers and calorimeters
based on tunnel junctions T. Faivre , D. Golubev, K. Viisanen and J.P. PekolaLow Temperature Detectors Workshop, July 20th
3
Outline
• NIS thermometer• RF-NIS micro-calorimeter• Quasiparticle thermometer• Limitation due to γ parameter
• Andreev current • Andreev reflection• Subgap leakage• Zero-bias anomaly• Andreev thermometer
• Conclusion
Out
line
4
RF-NIS micro-calorimeter
Fast electron thermometry towards ultra-sensitive calorimetric detection S.Gasparinetti et al., Phys. Rev. Appl. 3, 014007.
NIS
t her
mom
eter
VH
5
RF-NIS micro-calorimeter
NIS
t her
mom
eter
Incomplete measurement of work in a dissipative two level system K. Viisanen et al., New J. Phys. 17, 055014 (2015).
6
Quasi-particles thermometer
NIS
t her
mom
eter
100
mK
7 mK
Tunnel junction thermometry down to millikelvin temperatures A. Feshchenko et al., ArXiv 1504.03841 .
8
Outline
• NIS thermometer• RF-NIS micro-calorimeter• Quasiparticle thermometer• Limitation due to Andreev tunneling
• Andreev current • Andreev reflection• Subgap leakage• Zero-bias anomaly• Andreev thermometer
• Conclusion
Out
line
9
Andreev reflection
Subgap conductivity of a superconductor —normal-metal tunnel interface F.W.J. Hekking et al. , Phys.Rev.B, 49,6857 (1994).
And
reev
cu
rre
n t
10
Subgap leakage in SINIS devices
And
reev
cur
ren t
Experimentally,
Al (20 nm)
Ti (17 nm)
Al (3nm)AlOx
11
Zero-bias anomaly
Al (20 nm)
Au (10 nm)
Ti (20 nm)
Ti (2nm)Al (3nm)AlOx
Andreev Current for low temperature thermometry T. Faivre et al. , Appl. Phys. Lett. 106, 182602, (2015).
And
reev
cur
ren t
12
Zero-bias thermometer
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
2
4
6
8
10
12
x 105
Tbath
(K)
R0(
)
data
AndreevR
qp
Temperature saturation
qp saturation : I
Andreev current Ia,n
SINIS resistance
a,s fits
And
reev
cur
ren t
13
Perfomance
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
2
4
6
8
10
12
x 105
Tbath
(K)
R0(
)
data
AndreevR
qp
Temperature saturation
qp saturation : I
Andreev current Ia,n
SINIS resistance
a,s fits
And
reev
cur
ren t
14
Role of the Andreev current in bolometers and calorimeters based on tunnel junctions
Con
c lus
ion
Zero-bias thermometer :No shot noiseBetter heat insulation
But limited by Andreev tunneling
Andreev thermometer :Extend the temperature range toward mKConstant responsivity
15
Role of the Andreev current in bolometers and calorimeters based on tunnel junctions
Ref
er e
nce s
Incomplete measurement of work in a dissipative two level systemK.Viisanen et al., New J. Phys. 17, 055014 (2015).
Andreev Current for low temperature thermometry T. Faivre et al. , Appl. Phys. Lett. 106, 182602, (2015).
Tunnel junction thermometry down to millikelvin temperatures A. Feshchenko et al., ArXiv 1504.03841 (2015).
Fast electron thermometry towards ultra-sensitive calorimetric detection S.Gasparinetti et al., Phys. Rev. Appl. 3, 014007 (2015).
NIS thermometry
RF-NIS calorimetry
T. Faivre , D. Golubev, K.Viisanen and J.P. Pekola
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