Three-Terminal Superconducting Device Current Crowding Sensing
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Solution Overview
Problem
Conventional methods for sensing currents in superconducting channels often require magnetically coupling or perturbing the superconducting state, which can be cumbersome and alter the quantity being measured.
Innovation Solution
A three-terminal superconducting device is configured to detect current in a first channel by applying imbalanced current densities to a second channel, forming a region of measurable resistance or suppressing superconductivity, allowing current flow or voltage detection without perturbing the first channel's state, enabling dynamic threshold adjustment and rapid operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetically coupling or perturbing the superconducting state is used to sense current, then current sensing is achieved, but the superconducting state is altered and the measurement becomes cumbersome
Solution Approach 1:
The patent introduces a third superconducting channel as an intermediary element that indirectly senses the current in the first channel through magnetic coupling. This mediator channel allows current measurement without directly perturbing the original superconducting state, as the sensing is performed through the intermediary's response to the magnetic field generated by the measured current.
Solution Approach 2:
The patent replaces direct magnetic coupling methods with a field-effect mechanism where current control in one channel modulates the critical current of another channel. This substitution eliminates the need for physical magnetic coupling structures and simplifies the sensing operation to electrical current control.
2Productivity
If conventional superconducting switches switch large regions between superconducting and normal states, then switching capability is achieved, but switching speed becomes slow (microseconds)
Solution Approach 1:
The patent confines the superconducting state transition to a localized region near the channel intersection rather than switching the entire device. By applying current to one channel, only a small local region experiences the critical current modulation and state transition, while the rest of the superconducting material remains in its superconducting state. This localized approach dramatically reduces the volume of material that must be switched and enables faster switching speeds.
Solution Approach 2:
The patent divides the superconducting device into distinct functional channels, each carrying current independently. The switching action is segmented to affect only the necessary portion of the device (one channel's critical current) rather than requiring the entire device to transition states, enabling rapid localized switching.
3Speed
If Josephson junctions are used to achieve fast switching (picoseconds), then switching speed is improved, but device complexity and fabrication difficulty increase
Solution Approach 1:
The patent achieves fast switching by changing the current parameter in one channel, which modulates the critical current parameter of another channel. This parameter-based control approach eliminates the need for complex multi-layer Josephson junction structures, achieving picosecond-scale switching speeds through simpler single-layer superconducting material with controlled current parameters.
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
Enables non-invasive current sensing and control in superconducting channels, allowing for rapid switching and multiple read-outs of superconducting memory elements without altering their state, improving switching speed and operational reliability.
Implementation Method 1
A three-terminal superconducting device is configured to detect current in a first channel by applying imbalanced current densities to a second channel, forming a region of measurable resistance or suppressing superconductivity
Implementation Method 2
A three-terminal superconducting device may be activated by applying imbalanced current densities to two channels of the device that merge at the intersection region. When a sufficient imbalance is applied, either a hot spot (a region in a normal state having measurable resistance) will form in a second of the two channels or superconductivity will be suppressed in the second channel
Data Source
AI summary
An active three-terminal superconducting device having an intersection region at which a hot spot may be controllably formed is described. The intersection region may exhibit current crowding in response to imbalances in current densities applied to channels connected to intersection region. The current crowding may form a hot spot, in which the superconducting device may exhibit a measurable resistance. In some cases, a three-terminal superconducting device may be configured to sense an amount of superconducting current flowing in a channel or loop without having to perturb the superconducting state or amount of current flowing in the channel. A three-terminal superconducting device may be used to read out a number of fluxons stored in a superconducting memory element.