Nanosculpting lateral weak link junctions in superconducting Fe(Te,Se)/Bi2Te3 with focused Si++ ions and implications on vortex pinning

Fuente: arXiv
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Main Authors: Mallick, Debarghya, Ghosh, Sujoy, Chen, An Hsi, Lu, Qiangsheng, Collins, Liam, Kim, Sangsoo, Eres, Gyula, Kravchenko, Ivan, Jesse, Stephen, Randolph, Steven J., Retterer, Scott T., Brahlek, Matthew, Moore, Robert G.
Format: Preprint
Published: 2025
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author Mallick, Debarghya
Ghosh, Sujoy
Chen, An Hsi
Lu, Qiangsheng
Collins, Liam
Kim, Sangsoo
Eres, Gyula
Kravchenko, Ivan
Jesse, Stephen
Randolph, Steven J.
Retterer, Scott T.
Brahlek, Matthew
Moore, Robert G.
author_facet Mallick, Debarghya
Ghosh, Sujoy
Chen, An Hsi
Lu, Qiangsheng
Collins, Liam
Kim, Sangsoo
Eres, Gyula
Kravchenko, Ivan
Jesse, Stephen
Randolph, Steven J.
Retterer, Scott T.
Brahlek, Matthew
Moore, Robert G.
contents Superconductor-normal-superconductor (SC-N-SC) weak links enable Cooper-pair tunneling and serve as Josephson junctions (JJs) used in modern superconducting qubits. Conventional JJs rely on vertically stacked Al-AlOx-Al trilayers that are difficult to fabricate and are sensitive to ambient exposure. Here, we demonstrate an all-in-plane alternative by "nanosculpting" ~100 nm-wide channels into thin films of FeTe0.75Se0.25/Bi2Te3 (FTS/BT), a candidate topological superconductor, with a Si++ focusses ion beam (FIB). Systematic irradiation shows that increasing the ion dose, while keeping the beam energy constant, progressively suppresses both the critical temperature (Tc) and critical current (Ic), confirming the creation of a controllable weak link even though a Fraunhofer interference pattern is not observed. Kelvin prove force microscopy , atomic force microscopy and scanning electron microscopy corroborate the structural and electronic modification of the irradiated region. Ic (B) measurements reveal a slower field-induced decay of Ic at higher doses, indicating that irradiation-induced defects act as vortex-pinning centers that mitigate vortex motion and associated dissipation, By tuning beam energy and dose, the process shifts from SC-N-SC regime toward a superconductor-insulator-superconductor (SC-I-SC) geometry, offering a simple scalable pathway to JJ fabrication. These results established FIB pattering as a versatile platform for engineering robust, scalable fault-tolerant qubits.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10606
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nanosculpting lateral weak link junctions in superconducting Fe(Te,Se)/Bi2Te3 with focused Si++ ions and implications on vortex pinning
Mallick, Debarghya
Ghosh, Sujoy
Chen, An Hsi
Lu, Qiangsheng
Collins, Liam
Kim, Sangsoo
Eres, Gyula
Kravchenko, Ivan
Jesse, Stephen
Randolph, Steven J.
Retterer, Scott T.
Brahlek, Matthew
Moore, Robert G.
Superconductivity
Superconductor-normal-superconductor (SC-N-SC) weak links enable Cooper-pair tunneling and serve as Josephson junctions (JJs) used in modern superconducting qubits. Conventional JJs rely on vertically stacked Al-AlOx-Al trilayers that are difficult to fabricate and are sensitive to ambient exposure. Here, we demonstrate an all-in-plane alternative by "nanosculpting" ~100 nm-wide channels into thin films of FeTe0.75Se0.25/Bi2Te3 (FTS/BT), a candidate topological superconductor, with a Si++ focusses ion beam (FIB). Systematic irradiation shows that increasing the ion dose, while keeping the beam energy constant, progressively suppresses both the critical temperature (Tc) and critical current (Ic), confirming the creation of a controllable weak link even though a Fraunhofer interference pattern is not observed. Kelvin prove force microscopy , atomic force microscopy and scanning electron microscopy corroborate the structural and electronic modification of the irradiated region. Ic (B) measurements reveal a slower field-induced decay of Ic at higher doses, indicating that irradiation-induced defects act as vortex-pinning centers that mitigate vortex motion and associated dissipation, By tuning beam energy and dose, the process shifts from SC-N-SC regime toward a superconductor-insulator-superconductor (SC-I-SC) geometry, offering a simple scalable pathway to JJ fabrication. These results established FIB pattering as a versatile platform for engineering robust, scalable fault-tolerant qubits.
title Nanosculpting lateral weak link junctions in superconducting Fe(Te,Se)/Bi2Te3 with focused Si++ ions and implications on vortex pinning
topic Superconductivity
url https://arxiv.org/abs/2509.10606