P10 (Scheer): Spatially-resolved transport spectroscopy of quantum matter

• Applicant: Professorin Dr. Elke Scheer
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493158779

Hybrid devices of superconductor{ferromagnet (SC-FM) hybrid systems may support Cooper pairs with unconventional symmetry giving rise to long-ranged, spin polarized supercurrents (SPSC) through the ferromagnet. On the other hand, these systems may host Andreev bound states (ABS) or Majorana bound states (MBS). SPSC and MBS may be used in correlated quantum information technology for dissipationless information transfer by virtue of their entangled and coherent nature. However, the conditions to reliably create and detect MBS with these hybrid devices are still not settled, because details of the interface may play a crucial role and because the identification of MBS and distinguishing them from ABS solely by transport experiments is still a challenge. We hypothesize that knowing the spectral properties of low-energy excitations and their correlations and entanglement in highly-correlated quantum materials like Kondo systems close to a quantum critical point or high-Tc superconductors, is mandatory to leverage their potential for applications in solid state quantum systems. The central goal of this project part is to develop a route for detecting electronic correlations by combining scanning tunneling spectroscopy with electronic transport measurements. This project part complements the palette of detection techniques for these exotic electronic states, investigated throughout the whole SFB, by a local probe. It seeks to establish a correlation between the spatial dependence of the local density of states and current-voltage characteristics of devices made of unconventional material combinations. In particular we want to develop a scheme for distinguishing between MBS and ABS, identifying systems which may host long-ranged SPSCs, detect unconventional superconducting order parameter symmetries, contribute to the development of a Cooper pair splitter and to reveal the spatio-spectroscopic signatures of Kondo correlations.

• DFG Programme: Research Grants
• International Connection: Austria
• Cooperation Partner: Professorin Dr. Silke Bühler-Paschen