Search NASA⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3021697

Current-Phase Relations of Superconducting PtSi Constriction Josephson Junctions

Nanayakkara, Tharanga R. [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Bollinger, Anthony T. [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Musick, Kevin [NY CREATES, Albany, NY (United States)]·Murray, Thomas [NY CREATES, Albany, NY (United States)]·Bhatia, Ekta [NY CREATES, Albany, NY (United States)]·Papa Rao, Satyavolu [NY CREATES, Albany, NY (United States)] (ORCID:0000000258932535)·Black, Charles T. [Brookhaven National Laboratory (BNL), Upton, NY (United States)]·Liu, Mingzhao [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000209995214)
View original source ↗Read source document ↗Export metadata ↓

Abstract

Here, we study the current-phase relations of superconductor–constriction–superconductor Josephson junctions made from platinum silicide thin films by fabricating dc-superconducting quantum interference devices incorporating pairs of junctions and measuring their magnetic-field-dependent electrical transport. By comparing the supercurrent interference patterns with numerical Ginzburg–Landau simulations, we extract the current-phase relations of individual junctions and quantify the degree of nonlinearity. These measurements show that while the constrictions themselves sustain substantial nonlinearity, the effect is moderated by the kinetic inductance of the device leads, which is an important consideration for practical superconducting circuit applications.

Explore related subjects

77 NANOSCIENCE AND NANOTECHNOLOGYSQUIDconstrictioncurrent-phase relationsplatinum silicidesuperconductivity

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Nanayakkara, Tharanga R. [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Bollinger, Anthony T. [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Musick, Kevin [NY CREATES, Albany, NY (United States)], Murray, Thomas [NY CREATES, Albany, NY (United States)], Bhatia, Ekta [NY CREATES, Albany, NY (United States)], Papa Rao, Satyavolu [NY CREATES, Albany, NY (United States)] (ORCID:0000000258932535), Black, Charles T. [Brookhaven National Laboratory (BNL), Upton, NY (United States)], Liu, Mingzhao [Brookhaven National Laboratory (BNL), Upton, NY (United States)] (ORCID:0000000209995214). 2026-01-06. Current-Phase Relations of Superconducting PtSi Constriction Josephson Junctions. https://doi.org/10.1021/acs.nanolett.5c04738

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Gold Quantum Rods: Modulation of Singlet and Triplet Exciton Populations by the Rod Length

Abstract Gold quantum rods (QRs) of Au60, Au78, Au96, and Au114 (protected by thiolate ligands) exhibit exclusive fluorescence, which is different from the shorter Au42 QR with dual emission (fluorescence + phosphorescence). Herein, we report the excitation wavelength-dependent near-infrared-II photoluminescence (PL) and exciton dynamics of this series of QRs. Interestingly, the fluorescence quantum yield (QY) of the QRs is much higher (2–10×) when the lowest singlet excited state (S1) is excited compared to the excitation of high-lying states (Sn). A metastable intermediate singlet state (denoted S′) is identified by transient absorption spectroscopy when Sn is excited, and this S′ state leads to fast “skybridge” intersystem crossing (ISC), which contributes primarily (>60%) to the total triplet population. With increasing aspect ratio (AR) of QRs (from 6.3 to 18.7), nonradiative processes accelerate, leading to fast decay of the S1 state (hence, less QY) and of the T1 state (barely phosphorescent). A detailed energy flow mechanism is determined for the QRs after photoexcitation, which offers a design principle for manipulation of exciton dynamics toward potential utilization of higher excited states in applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2026

Demonstration of gold nanorod systems for enhanced total efficiency: Experimental and numerical analysis

This study investigates the photothermal performance of gold nanorods engineered to exhibit longitudinal plasmon resonances at 695 nm, 780 nm, and 970 nm. The work combines synthesis, structural characterization, extinction measurements, numerical modeling, and controlled temperature experiments to quantify how nanorod geometry, resonance tuning, concentration, and chamber shape jointly influence heat generation. Transmission electron microscopy confirms that increasing nanorod aspect ratio systematically shifts the longitudinal plasmon peak toward the near-infrared region. Extinction measurements show strong agreement with theoretical predictions, validating the numerical model across two independent datasets. Three chamber geometries were tested under laser excitation at 640 nm, 808 nm, and 980 nm: an ascending stepped base, a flat base, and a descending stepped base. Without nanorods, the ascending geometry produced the highest efficiency due to enhanced natural convection. After introducing gold nanorods, all geometries exhibited substantial thermal enhancement, with total efficiencies exceeding 20%. The strongest improvement was obtained for nanorods resonant at 780 nm with a mass concentration of 4.6 mg/mL implemented on the descending stepped-base geometry. This performance resulted from the combined effect of spectral overlapping with the 808 nm laser, the highest nanorod concentration, and localized heat accumulation that intensified buoyancy-driven flow. The findings demonstrate that total efficiency is governed by a synergistic interplay between optical resonance, nanoparticle concentration, and macroscopic chamber design, revealing the system-level coupling between nanoscale plasmonic absorption and macroscale heat-transfer phenomena. The results provide a validated framework for tuning nanoscale plasmonic absorbers and optimizing thermal systems for applications requiring efficient light-to-heat conversion.

77 NANOSCIENCE AND NANOTECHNOLOGY↗