arXiv subjects

A. J. Muhowski

Publications and source records attributed to A. J. Muhowski.

3 recordsLinked to original sources

arXiv2025

Epitaxial aluminum layer on antimonide heterostructures for exploring Josephson junction effects

In this article, we present results of our recent work of epitaxially-grown aluminum (epi-Al) on antimonide heterostructures, where the epi-Al thin film is grown at either room temperature or below zero $^o$C. A sharp superconducting transition at $T \sim 1.3$ K is observed in these epi-Al films. We further show that supercurrent states are realized in Josephson junctions fabricated in the epi-Al/antimonide heterostructures with mobility $μ\sim 1.0 \times 10^6$ cm$^2$/Vs. These results clearly demonstrate we have achieved growing high-quality epi-Al/antimonide heterostructures, a promising platform for the exploration of Josephson junction effects for quantum information science and microelectronics applications.

cond-mat.mtrl-sci↗

arXiv2024

Quantum Enhanced Josephson Junction Field-Effect Transistors for Logic Applications

Josephson junction field-effect transistors (JJFETs) have recently re-emerged as promising candidates for superconducting computing. For JJFETs to perform Boolean logic operations, the so-called gain factor $α_{R}$ must be larger than 1. In a conventional JJFET made with a classical channel material, due to a gradual dependence of superconducting critical current on the gate bias, $α_{R}$ is much smaller than 1. In this Letter, we propose a new device structure of quantum enhanced JJFETs in a zero-energy-gap InAs/GaSb heterostructure. We demonstrate that, due to an excitonic insulator quantum phase transition in this zero-gap heterostructure, the superconducting critical current displays a sharp transition as a function of gate bias, and the deduced gain factor $α_{R}$ ~ 0.06 is more than 50 times that (~ 0.001) reported in a classical JJFET. Further optimization may allow achieving a gain factor larger than 1 for logic applications.

cond-mat.supr-con↗

arXiv2022

High operating temperature plasmonic infrared detectors

III-V semiconductor type-II superlattices (T2SLs) are a promising material system with the potential to significantly reduce the dark current of, and thus realize high-performance in, infrared photodetectors at elevated temperatures. However, T2SLs have struggled to meet the performance metrics set by the longstanding infrared detector material of choice, HgCdTe. Recently, epitaxial plasmonic detector architectures have demonstrated T2SL detector performance comparable to HgCdTe in the 77 K - 195 K temperature range. Here we demonstrate a high operating temperature plasmonic T2SL detector architecture with high-performance operation at temperatures accessible with two-stage thermoelectric coolers. Specifically, we demonstrate long-wave infrared plasmonic detectors operating at temperatures as high as 230 K while maintaining dark currents below the "Rule 07" heuristic. At a detector operating temperature of 230 K, we realize 22.8% external quantum efficiency in a detector absorber only 372 nm thick ($\simλ_0 /25$) with peak specific detectivity of $2.29x10^{9}$ cm Hz$^{1/2}$ W$^{-1}$ at 9.6 $μ$m, well above commercial detectors at the same operating temperature.

physics.optics↗