APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

30 Jul 2012

Volume 101, Issue 5, Articles (05xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 101, 051103 (2012); http://dx.doi.org/10.1063/1.4738774 (4 pages)

Alec Rose, Da Huang, and David R. Smith
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Energy-resolved detection of single infrared photons with λ = 8 μm using a superconducting microbolometer

Boris S. Karasik, Sergey V. Pereverzev, Alexander Soibel, Daniel F. Santavicca, Daniel E. Prober, David Olaya, and Michael E. Gershenson

Appl. Phys. Lett. 101, 052601 (2012); http://dx.doi.org/10.1063/1.4739839 (5 pages) | Cited 1 time

Online Publication Date: 30 July 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the detection of single photons with λ = 8 μm using a superconducting hot-electron microbolometer. The sensing element is a titanium transition-edge sensor with a volume ∼0.1 μm3 fabricated on a silicon substrate. Poisson photon counting statistics including simultaneous detection of 3 photons was observed. The width of the photon-number peaks was 0.11 eV, 70% of the photon energy, at 50–100 mK. This achieved energy resolution is one of the best figures reported so far for superconducting devices. Such devices can be suitable for single-photon calorimetric spectroscopy throughout the mid-infrared and even the far-infrared.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
85.25.Pb Superconducting infrared, submillimeter and millimeter wave detectors

Direct current superconducting quantum interferometers with asymmetric shunt resistors

M. Rudolph, J. Nagel, J. M. Meckbach, M. Kemmler, M. Siegel, K. Ilin, D. Koelle, and R. Kleiner

Appl. Phys. Lett. 101, 052602 (2012); http://dx.doi.org/10.1063/1.4739850 (4 pages)

Online Publication Date: 30 July 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated asymmetrically shunted Nb/Al-AlOx/Nb direct current (dc) superconducting quantum interference devices (SQUIDs). While keeping the total resistance R identical to a comparable symmetric SQUID with R−1 = R1−1+R2−1, we shunted only one of the two Josephson junctions with R = R1,2/2. Simulations predict that the optimum energy resolution ϵ and thus also the noise performance of such an asymmetric SQUID can be 3–4 times better than that of its symmetric counterpart. Experiments at a temperature of 4.2 K yielded ϵ ≈ 32 ℏ for an asymmetric SQUID with an inductance of 22 pH. For a comparable symmetric device, ϵ = 110 ℏ was achieved, confirming our simulation results.
Show PACS
85.25.Dq Superconducting quantum interference devices (SQUIDs)
84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)
85.25.Cp Josephson devices

Superconducting microstrip amplifiers with sub-Kelvin noise temperature near 4 GHz

M. P. DeFeo and B. L. T. Plourde

Appl. Phys. Lett. 101, 052603 (2012); http://dx.doi.org/10.1063/1.4742164 (4 pages) | Cited 1 time

Online Publication Date: 31 July 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present measurements of an amplifier operating at 3.8 GHz with 150 MHz of bandwidth based on the microstrip input-coil resonance of a dc superconducting quantum interference device (SQUID) with submicron Josephson junctions. The noise temperature is measured using two methods: comparing the signal-to-noise ratio of the system with and without the SQUID in the amplifier chain, and using a modified Y-factor technique where calibrated narrowband noise is mixed up to the SQUID amplifier operating frequency. With the SQUID cooled to 0.35 K, we observe a minimum system noise temperature of 0.55 ± 0.13 K, dominated by the contribution from the SQUID amplifier.
Show PACS
85.25.Dq Superconducting quantum interference devices (SQUIDs)

Phase stability and superconductivity of strontium under pressure

Duck Young Kim, Pornjuk Srepusharawoot, Chris J. Pickard, Richard J. Needs, Thiti Bovornratanaraks, Rajeev Ahuja, and Udomsilp Pinsook

Appl. Phys. Lett. 101, 052604 (2012); http://dx.doi.org/10.1063/1.4742323 (4 pages)

Online Publication Date: 2 August 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have used the ab initio random structure searching method together with density functional theory calculations to find stable structures of strontium under pressures up to 50 GPa. We predict a sequence of structural phase transitions and the stability of an orthorhombic structure of Cmcm symmetry above 25 GPa. Our energy, lattice dynamics, and molecular dynamics calculations confirm the stability of the Cmcm structure. The electron-phonon coupling calculations show that superconductivity arises in the bcc structure of compressed Sr and that it continues to exist in the Cmcm structure. The calculated superconducting transition temperatures are in good agreement with experiment. Our study gives an excellent account of the experimental observations.
Show PACS
74.62.-c Transition temperature variations, phase diagrams
63.20.kd Phonon-electron interactions
61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling

The electrical conductivity of bundles of superconducting nanowires produced by laser ablation of metals in superfluid helium

E. B. Gordon, A. V. Karabulin, V. I. Matyushenko, V. D. Sizov, and I. I. Khodos

Appl. Phys. Lett. 101, 052605 (2012); http://dx.doi.org/10.1063/1.4742330 (5 pages) | Cited 2 times

Online Publication Date: 2 August 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temperature dependencies of the electrical resistance are reported for bundles of permalloy, indium, tin, and lead nanowires having a similar diameter of about 8 nm which were grown by catalytic coagulation of laser ablation products in quantized vortices of superfluid helium. In all metals, the constant residual resistance found at low temperatures changes to a superlinear growth at higher temperatures. For all superconducting nanowires, the transition to superconductivity is broadened with a width of δT = 0.6 K. The size shift of the transition center ΔT is largest for lead, ΔT = −2 K, whereas for indium and tin ΔT is 0.2 K and <0.1 K, respectively.
Show PACS
74.25.fc Electric and thermal conductivity
73.63.Bd Nanocrystalline materials
74.70.Ad Metals; alloys and binary compounds (including A15, MgB2, etc.)
74.78.Na Mesoscopic and nanoscale systems
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close