Three-Terminal Josephson Junction Superconducting Diode
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current superconducting devices lack a reliable method to achieve a non-reciprocal current flow, essential for realizing a superconducting diode effect, which is crucial for applications like signal rectification and oscillators, due to the absence of a mechanism to differentiate between current flow directions.
Innovation Solution
A three-terminal Josephson device is designed with a Josephson junction and epitaxial aluminum layer, where the gate layer includes three gates extending across channels between terminal pairs, enabling a superconducting current in one direction and a dissipative current in the opposite direction, with tunability via an out-of-plane magnetic field or electrostatic gating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional diode structure is used to achieve non-reciprocal current flow, then current rectification is possible, but the device cannot be superconducting due to inherent resistance
Solution Approach 1:
The patent applies asymmetry by creating a three-terminal Josephson junction with asymmetric coupling between terminals, where the coupling strength between terminal 0 and terminal 1 differs from the coupling between terminal 0 and terminal 2. This asymmetric configuration breaks the reciprocity of current flow, enabling different critical currents in opposite directions while maintaining the superconducting state through the Josephson effect.
Solution Approach 2:
The patent transitions from a conventional two-terminal diode to a three-terminal Josephson junction, adding an additional terminal dimension. This dimensional change enables new degrees of freedom for controlling current flow directions and implementing non-reciprocal behavior through the unique properties of multi-terminal superconducting circuits.
2Ease of operation
If a three-terminal Josephson junction is designed to achieve non-reciprocal supercurrent flow, then superconducting diode effect is realized, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into a single three-terminal Josephson junction device, combining the functions of current rectification, superconducting state maintenance, and magnetic field sensing/detection within one integrated structure. This merging approach achieves non-reciprocal supercurrent flow without requiring separate components for each function, thereby managing complexity.
3Ease of operation
If the coupling between terminals is made asymmetric to enable diode effect, then non-reciprocal current flow is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes parameter changes by adjusting the coupling strength between terminals as a controllable variable. The asymmetric coupling is achieved by modifying physical parameters such as junction area, barrier thickness, or material composition in different terminal pairs, allowing precise control over the degree of asymmetry and enabling tuning of the diode effect strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively demonstrates a superconducting diode effect with tunable diode efficiency, allowing for scalable and robust implementation in various applications, including topologically protected qubits and neuromorphic computing, by achieving non-reciprocal supercurrent flow and rectification.
Implementation Method 1
A Josephson junction may be defined between at least three terminals. A super-current may flow in a first direction between a terminal pair of the three terminals
Implementation Method 2
The out-of-plane magnetic field may be configured to tune a diode efficiency of the device
Data Source
AI summary
A device may include a Josephson junction between at least three terminals. The device is configured to exhibit a superconducting diode effect. A method may include forming a Josephson layer including three terminals defining a Josephson junction. The method may further include forming, over the Josephson layer, a gate layer including at least three gates. Each gate of the at least three gates extends across a respective channel between a respective terminal pair of the three terminals. The Josephson layer and gate layer are configured to exhibit a superconducting diode effect.