Patrik Hlobil

Coupling to real and virtual phonons in tunneling spectroscopy of superconductors

Fine structures in the tunneling spectra of superconductors have been widely used to identify fingerprints of the interaction responsible for Cooper pairing. Here, we show that for scanning tunneling microscopy (STM) of Pb, the inclusion of inelastic tunneling processes is essential for the proper interpretation of these fine structures. For STM the usual McMillan inversion algorithm of tunneling spectra must therefore be modified to include inelastic tunneling events, an insight that is crucial for the identification of the pairing glue in conventional and unconventional superconductors alike.

Tracing the Electronic Pairing Glue in Unconventional Superconductors via Inelastic Scanning Tunneling Spectroscopy

Scanning tunneling microscopy has been shown to be a powerful experimental probe to detect electronic excitations and further allows us to deduce fingerprints of bosonic collective modes in superconductors. Here, we demonstrate that the inclusion of inelastic tunnel events is crucial for the interpretation of tunneling spectra of unconventional superconductors and allows us to directly probe electronic and bosonic excitations via scanning tunneling microscopy. We apply the formalism to the iron based superconductor LiFeAs. With the inclusion of inelastic contributions, we find strong evidence for a nonconventional pairing mechanism, likely via magnetic excitations.

Symmetry constraints on the elastoresistivity tensor

The elastoresistivity tensor

Elastoconductivity as a probe of broken mirror symmetries

m_{ij,kl}

Luminescence and squeezing of a superconducting light-emitting diode

characterizes changes in a materials resistivity due to strain. As a fourth-rank tensor, elastoresistivity can be a uniquely useful probe of the symmetries and character of the electronic state of a solid. We present a symmetry analysis of

Strong coupling behavior of the neutron resonance mode in unconventional superconductors

m_{ij,kl}

Unconventional pairing in single FeSe layers

(both in the presence and absence of a magnetic field) based on the crystalline point group, focusing for pedagogic purposes on the

Unconventional pairing versus phonon mediated superconductivity in single FeSe layers

D_{4h}

Fingerprints of the superconducting pairing glue via inelastic tunneling spectroscopy

point group (of relevance to several materials of current interest). We also discuss the relation between

Elastoconductivity measurements as a probe of broken mirror symmetries

m_{ij,kl}