Superconducting Memory Cells: Capacitive Coupling for Reliable Integration
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Solution Overview
Problem
Existing memory devices based on superconductors suffer from limited reliability and integration challenges with other superconducting components.
Innovation Solution
The development of thin film memory cells utilizing superconducting materials, featuring a loop and wire configuration that allows for capacitive coupling and persistent current storage, with controlled phase transitions to manage data storage and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior memory devices use superconductors, then they can operate with zero electrical resistance, but they have limited reliability
Solution Approach 1:
The memory cell is divided into distinct functional components: a superconducting loop for data storage and a separate wire for control signals. This segmentation allows each component to be optimized independently, improving reliability while maintaining manageable complexity.
Solution Approach 2:
A capacitor is introduced as an intermediary element between the superconducting loop and the control wire. This capacitor enables controlled coupling and decoupling, facilitating reliable data storage and retrieval operations while simplifying the integration of superconducting components with conventional control circuitry.
2Ease of manufacture
If superconducting materials are used in memory cells, then zero resistance is achieved under certain conditions, but integration with other superconducting components becomes challenging
Solution Approach 1:
The superconducting loop structure serves multiple functions: it acts as both the storage element and the interface for control signals. This multi-functionality reduces the number of separate components needed, thereby simplifying integration with other superconducting components in the circuit.
Solution Approach 2:
The capacitor serves as a universal interface element that can couple the superconducting loop with various types of control circuits, whether superconducting or conventional. This intermediary simplifies the integration process by providing a standardized interface.
3Reliability
If a loop structure is used for persistent current storage, then data retention is improved, but the device requires precise capacitive coupling control
Solution Approach 1:
The coupling between the capacitor and the superconducting loop is controlled by changing the state of the superconducting wire (superconducting vs. normal resistive state). This parameter change allows dynamic control of capacitive coupling without requiring precise physical positioning, thereby reducing manufacturing precision requirements while maintaining reliable data storage.
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
Enhances operational reliability and ease of integration with superconducting circuits, enabling seamless operation in sensitive applications like quantum computing and SQUIDs.
Implementation Method 1
a layer of superconducting material disposed over the substrate. The layer of superconducting material is patterned to form a plurality of distinct instances of the layer of superconducting material including: a first wire and a loop that is (i) distinct and separate from the first wire and (ii) capacitively coupled to the first wire while the loop and the first wire are in a superconducting state
Implementation Method 2
the loop is capacitively coupled to the first wire while the loop and the first wire are in a superconducting state. The loop is configured to form a persistent current via the capacitive coupling in response to a write current applied to the first wire
Data Source
AI summary
An example memory device includes an array of superconducting memory cells, each memory cell of the array of superconducting memory cells comprising a superconducting loop capacitively coupled to a read line and a write line. The example memory device further includes circuitry configured to address a respective memory cell in the array of superconducting memory cells so as to direct at least one of a write signal and a read signal to the respective memory cell.