Interplay between High-Temperature Superconductivity, Magnetism and Composition in Doped Cuprates

2026-07-22

The origin of high-temperature (high-T) superconductivity (SC) is one of the greatest unsolved problems in physics. The solution could potentially lead to room temperature SC with immense technological benefits. There is ample evidence that microscopic magnetic correlations and dynamics are coupled to high-T SC, but a true understanding remains. The proposed research focusses on the effect of dopants on magnetic and SC properties of La2-xSrxCuO4 (LSCO) cuprates. The main research question is: does the SC mechanism has its origin in the magnetic properties of the material? This will be tackled in three ways: 1) The applicant will determine if the new theoretical prediction of the SC transition temperature increase with very small impurity content is justified for LSCO. This whole new effect will strengthen the case for magnetism-induced SC. 2) The applicant will study the low-temperature magnetic phase of LSCO when SC is fully suppressed by doping and field to provide new insights into the nature of intrinsic magnetic tendencies of LSCO. 3) The applicant will synthesize single crystals of completely new cuprates by replacing Sr by Sn, Zr and Ga to study how the ionic radii affect the magnetism-SC interplay. The project involves crystal synthesis, XRD, VSM and transport measurements and has a strong focus on elastic and inelastic neutron scattering experiments and data analysis. The applicant’s physics background and PhD in materials chemistry provide a strong basis for the experiments. The interdisciplinary nature of UCPH creates the ideal environment: the main supervisor Prof. Lefmann is an expert in neutron scattering with decades of experience, has all necessary physical characterization equipment and is a well-appreciated academic teacher. All relevant chemistry infrastructure and knowledge can be found within UCPH and close collaborators. In return, the applicant’s expertise in materials and crystallography will be a great addition to the Lefmann group.

Denmark

2026-02-01