Ultralow temperature nanorefrigerator

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Ultralow temperature nanorefrigerator
Cooling
Gn
Electron system
Electrical environment
Lattice
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NIS junction as a refrigerator
Cooling power of a NIS junction
Optimum cooling power is reached at VC ? 2D/e
Optimum cooling power per junction, when
superconducting reservoirs are not overheated, TS
ltlt TC
Temperature TN on the island is determined by the
balance of heat fluxes, e.g.
(dominates at high temperatures, negligible at
low temperatures)
Electron-phonon heat flux
Efficiency (coefficient of performance) of a NIS
junction refrigerator
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Experimental status
Nahum, Eiles, Martinis 1994 Demonstration of NIS
cooling Leivo, Pekola, Averin 1996, Kuzmin 2003,
Rajauria et al. 2007 Cooling electrons 300 mK -gt
100 mK by SINIS Manninen et al. 1999 Cooling by
SISIS see also Chi and Clarke 1979 and Blamire
et al. 1991, Tirelli, Giazotto et al.
2008 Manninen et al. 1997, Luukanen et al. 2000
Lattice (membrane) refrigeration by SINIS Savin
et al. 2001 S Schottky Semic Schottky S
cooling Clark et al. 2005, Miller et al. 2008
x-ray detector refrigerated by SINIS
Refrigeration of a membrane with separate
thermometer
Refrigeration of a bulk object
A. Clark et al., Appl. Phys. Lett. 86, 173508
(2005).
A. Luukanen et al., J. Low Temp. Phys. 120, 281
(2000).
For a review, see Rev. Mod. Phys. 78, 217 (2006).
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NIST 2007-08

• Done
• Robust, wafer-scale solid-state refrigerators
• 1st cooling of bulk material
• 1st integrated NIS-cooled detectors
• mm bolometer (Goddard)
• X-ray microcalorimeter
• Spectra above Tc

• Future (someone else)
• Improve cooling
• 300 ? 100 mK
• Cooling platform for general payloads
• Attach your own detector chip

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Specifications, objectives
Now Temperature reduction (electrons) 300 mK -gt
50 mK Temperature reduction (lattice) 200 mK -gt
100 mK Cooling power 30 pW at 100 mK by one
junction pair Objectives (NanoFridge, EPSRC,
Microkelvin) Electron cooling from 300 mK -gt 10
mK Cooled platform for nanosamples 300 mK -gt 50
mK, cooling power 10 nW at 100 mK by an array of
junctions Cooler from 1.5 K down to 300 mK using
higher Tc superconductor Experiments in progress
at TKK Thermodynamic cycles with electrons
utilizing Coulomb blockade, heat pump with P
kBT f (proposal 2007) Refrigeration at the
quantum limit (Meschke et al., Nature 2006,
Timofeev et al. 2009, unpublished) Brownian
refrigerator, Maxwells demon (proposal
2007) Cooling mechanical modes in suspended
structures, i.e., nanomechanics combined with
electronic refrigeration (Preliminary experiment,
Muhonen et al. and Koppinen et al. 2009)
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JRA2Ultralow temperature nanorefrigeratorTKK,
CNRS, RHUL, SNS, BASEL, DELFT
Objectives Thermalizing and filtering electrons
in nanodevices To develop an electronic
nano-refrigerator that is able to reach sub-10 mK
electronic temperatures To develop an electronic
microrefrigerator for cooling galvanically
isolated nanosamples
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Roles of the participants
TKK and CNRS will develop the nanorefrigeration
by superconducting tunnel junctions SNS will
build coolers based on semiconducting electron
gas BASEL will work mainly on very low
temperature thermalization and filtering DELFT
and RHUL are mainly end users of the nano-coolers
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Task 1 Thermalizing electrons in
nanorefrigerators (TKK, CNRS, BASEL)
Ex-chip filtering Sintered heat exchangers in a
3He cell Lossy coaxes/strip lines, powder
filters, ... On-chip filtering Lithographic
resistive lines SQUID-arrays
W. Pan et al., PRL 83, 3530 (1999)
A. Savin et al., APL 91, 063512 2007
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Task 2 Microkelvin nanocooler (TKK, CNRS, SNS)
Aim is to develop sub - 10 mK electronic
cooler Normal metal superconductor tunnel
junctions-based optimized coolers (TKK, CNRS,
DELFT) 10 mK to lower T Improved quality of
tunnel junctions Thermometry at low T? Lower Tc
superconductor Quasiparticle relaxation studies
in sc and trapping of qps Quantum dot cooler
(SNS)
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Thermometry at low T
SNS Josephson junction
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Task 3 Development of a 100 mK, robust,
electronically-cooled platform based on a 300 mK
3He bath (TKK, CNRS, RHUL, DELFT)
Commercial, robust SiN membranes (and custom made
alumina) as platforms (TKK) Epitaxial large area
junctions (CNRS) Optimized junctions (e-beam and
mechanical masks) RHUL and DELFT use these
coolers for experiments on quantum devices
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Deliverables
Task 1 D1 Analysis of combined ex-chip and
on-chip filter performance (18) D2 Demonstration
of sub-10 mK electronic bath temperature of a
nano-electronic tunnel junction device achieved
by the developed filtering strategy (30) Task
2 D3 Analysis of sub-10 mK nano-cooling
techniques including (i) traditional N-I-S cooler
with low Tc, (ii) quantum dot cooler (24) D4
Demonstration of sub-10 mK nanocooling with a
N-I-S junction (48) Task 3 D5 Demonstration of
300 mK to about 50 mK cooling of a dielectric
platform (36) D6 Demonstration of cooling-based
improved sensitivity of a quantum detector (48)