Related Experiment Video
Updated: Jan 6, 2026
05:39
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
10.2K
Voltage-Tuned Anomalous-Metal to Metal Transition in Hybrid Josephson Junction Arrays
S Sasmal1, M Efthymiou-Tsironi1,2, G Nagda1
1University of Copenhagen, Center for Quantum Devices, Niels Bohr Institute, 2100 Copenhagen, Denmark.
Physical Review Letters
|October 25, 2025
Summary
Researchers explored voltage-tuned phase transitions in hybrid semiconductor-superconductor islands. They discovered an anomalous metallic phase interrupting the superconductor-insulator transition, showing unique low-temperature resistivity properties.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Phenomena
Background:
- Hybrid semiconductor-superconductor systems are crucial for exploring quantum phenomena.
- Understanding phase transitions in such systems is key to developing novel electronic devices.
- Tuning electronic properties through electrostatic gating offers precise control.
Purpose of the Study:
- To investigate voltage-tuned phase transitions in hybrid semiconductor-superconductor island arrays.
- To explore emergent intermediate phases and critical points.
- To characterize an anomalous metallic phase and its suppression by magnetic frustration.
Main Methods:
- Fabrication of hybrid semiconductor-superconductor islands in a square lattice.
- Utilizing a double-layer electrostatic gate for independent tuning of coupling and superconductivity.
- Measuring resistivity across a wide range of gate voltages and temperatures.
Main Results:
- Achieved independent control over interisland coupling and proximity-induced superconductivity.
- Observed superconductor-insulator, superconductor-metal, and metal-insulator transitions in a single device.
- Identified an anomalous metallic phase with saturating low-temperature resistivity, tunable into a conventional metallic phase.
- Demonstrated suppression of the anomalous metallic phase by magnetic frustration.
Conclusions:
- The study provides a versatile platform for exploring diverse phase transitions in hybrid systems.
- An anomalous metallic phase with unique properties exists and can be tuned.
- Magnetic frustration plays a role in suppressing this anomalous metallic behavior.
Related Concept Videos
01:27Biasing of Metal-Semiconductor Junctions
511
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
511
01:24Metal-Semiconductor Junctions
859
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
859
01:16Biasing of P-N Junction
1.7K
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
1.7K
01:17Theory of Metallic Conduction
1.7K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.7K
01:22MOSFET: Enhancement Mode
739
Enhancement-mode MOSFETs are pivotal components in electronics, distinguished by their capacity to act as highly efficient switches. They are part of the larger family of metal-oxide Semiconductor Field-Effect Transistors (MOSFETs). They are available in two types: p-channel and n-channel, each tailored to specific polarity operations.
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no...
In their basic form, enhancement-mode MOSFETs are typically non-conductive when the gate-source voltage (Vgs) is zero. This default 'off' state means no...
739
01:11P-N junction
1.1K
A p-n junction is formed when p-type and n-type semiconductor materials are joined together. At the interface of the p-n junction, holes from the p-side and electrons from the n-side begin to diffuse into the opposite sides due to the concentration gradient. This diffusion of carriers leads to a region around the junction where there are no free charge carriers, known as the depletion region. The charge density within the depletion region for the n-side and p-side can be described by the...
1.1K