Overdoping HTS films: the route to get closer to the maximum departing current

Overdoping high-temperature superconducting (HTS) films is probably the major critical challenge to boost performance to the extreme limits, as increasing the carrier density enhances the condensation energy directly increasing the vortex pinning force. This project will investigate strategies to achieve and control overdoping in REBa₂Cu₃O₇₋ₓ (REBCO) thin films, including Ca-doped compositions, to access higher doping levels. The films will be prepared via the novel Transient Liquid Assisted Growth (TLAG) process developed at ICMAB, which is compatible with coated conductor architectures and nanocomposites.

In-situ resistivity measurements will be performed to monitor doping dynamics, using platforms such as the Joint Transition Energy Lab at the ALBA synchrotron. High oxygen-pressure experiments will be conducted in collaboration with IFW Dresden, while electrochemical and surface-activation strategies will be explored to enhance oxygen adhesion, dissociation, and diffusion, in collaboration with INPG Grenoble and TUW Viena. Oxygen isotope exchange (¹⁸O) studies combined with depth-resolved SIMS will provide detailed insight into oxygen incorporation, while ARPES experiments will allow direct determination of the Fermi surface and doping state.

Comprehensive characterization of the overdoped films will include charge carrier density, critical temperature, critical current, and superconducting properties under high magnetic fields. By correlating these properties with oxygen content, diffusion pathways, and structural modifications, the project aims to establish a clear understanding of the mechanisms governing enhanced pinning by increased condensation energy. By combining TLAG growth, targeted chemical doping, in-situ monitoring, isotope labeling, and advanced spectroscopy, this research will provide a roadmap for engineering overdoped HTS films with optimized superconducting performance. The outcomes will inform the design of next-generation superconducting coated conductors with a robust process capable to be easily integrated at industrial scale.

The position requires:

• Bachelor and master in physics, material science, nanoscience or related fields.
• Good knowledge in Condensed Matter Physics
• A high level of English. All working meetings are held in English
• High motivation to experimental research.
• Working aptitudes in a collaborative group.

Experience and knowledge on superconductivity, superconducting materials will be valuable

The candidate will join the Superconducting Materials Group, an international and interdisciplinary team with over 25 years’ expertise in High Temperature Superconductors (HTS). Superconductivity, a macroscopic quantum phenomenon from electron pairing (Cooper pairs), enables lossless current transport with broad applications. Since the discovery of cuprates, HTS coated conductors (CCs) have been developed for high-current, energy-efficient uses: power cables, wind generators, electrical aviation, compact fusion, colliders, or NMR beyond 1 GHz. Fusion is now a main driver of this expanding technology. Yet, device integration requires CC customization to meet electromagnetic, thermal, or mechanical demands. SUMAN has long advanced this goal through industrial collaborations, a strategy continued in emerging superconducting energy technologies and High Energy Physics (circular accelerators, axion cavities, muon colliders). Research focuses on CC growth and physics under device conditions vision and their tailored implementation with international partners.

ICMAB Institute offers excellent conditions for PhD students, including:

• A creative, world-class interdisciplinary research environment for fundamental and applied science 
• State-of-the-art infrastructure for the preparation and characterization of structured materials
• A highly regarded scientific education
• A strong international science network.