A preprint reports an association between pulsed electrical stress and highly selective resistance changes in individual branches of three-terminal devices made from YBCO, a superconducting material. The terminal receiving the stress changed significantly, while neighboring terminals showed only slight decreases in resistance.
It also reports that opposite current polarities were associated with opposite inferred directions for oxygen vacancies, places where oxygen is missing in the material. The reported oxygen-depleted fronts could either diverge or converge.
A targeted electrical test
The devices were fabricated from 50-nanometre-thick epitaxial YBCO thin films grown on SrTiO3 and patterned into a three-terminal geometry. The electrical protocol used 12-millisecond current pulses followed by a 12-second low-current window for probing.
Electrical stress was applied in negative or positive polarity to a selected terminal. The procedure was typically stopped when the device’s minimum resistance, recorded as Rmin, had risen by 5 per cent relative to its initial value.
The result was a branch-level contrast rather than a uniform shift across the device: the stressed terminal changed significantly, while neighboring terminals showed only slight decreases in resistance.
Following the oxygen pattern
Changes in optical reflectivity directly visualized oxygen-depleted fronts as they propagated through the device, and the optical changes were linked to the electrical response. The measurement added a spatial view to the resistance record.
Scanning Laser Microscopy, or SLM, enabled oxygen-content mapping from approximately 6.50 in the targeted terminal to approximately 6.85 in pristine regions. The map described the contrast between the targeted and pristine parts of the device on an oxygen-content scale.
Kelvin Probe Force Microscopy measured an approximately 0.30-electron-volt work-function difference between the potential minimum and the pristine region. That supplied another local measurement alongside the optical and resistance results.
The electrical state relaxed
After electromigration, the resistance state relaxed. Relaxation was weak at 225 kelvin during 120 minutes of monitoring, but became more apparent at higher temperatures. Between 300 and 330 kelvin, fitted time constants ranged from 13.75 minutes to 2.08 minutes.
An Arrhenius fit, which relates the rate of a process to temperature, gave an activation energy of 0.52 ± 0.01 electron volts. Together with the fitted time constants, that result describes a relaxation process that accelerated as the temperature increased.
A finite-element computer model qualitatively reproduced the main experimental trends, including selective depleted fronts and the relaxation of prior oxygen gradients. The agreement was qualitative rather than an exact numerical reproduction.
A result limited to the test system
Taken together, the measurements show branch-selective resistance changes, polarity-associated directions for inferred oxygen-vacancy movement, optical detection of depleted fronts and temperature-dependent relaxation in the studied YBCO devices. The evidence describes a device-level pattern in this experimental system.
The document is an arXiv version 1 preprint dated 26 August 2026. Its main supporting data are available through the Université de Liège Dataverse repository, with additional data available from the corresponding authors upon reasonable request.
Online supplementary material includes additional relaxation-history, positive-polarity electromigration and nanoprobe X-ray diffraction results.
Paper data and sources
Original title: Electrical manipulation of oxygen stoichiometry in multiterminal YBa$_2$Cu$_3$O$_{7-δ}$ junctions
Authors: Daniel Stoffels, Caio C. Quaglio-Gomes, Nicolas Lejeune et al.
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-26
DOI: Not available
Original paper · Full text