arXiv subjects

Kilian Srowik

Publications and source records attributed to Kilian Srowik.

2 recordsLinked to original sources

arXiv2026

Probing bulk superconductivity in centrosymmetric Te-doped PtBi$_2$ single crystals

The Weyl semimetal $γ$-PtBi$_2$ has been shown to be one of the most promising novel materials, recently proposed as a topological i-wave superconductor. A crucial requirement for observing this physics is the absence of inversion symmetry in its trigonal $P31m$ crystal structure. Centrosymmetry has been reported to be readily restored in the $P\overline{3}m1$ structure upon electron doping, partially substituting Bi with as little as 2% Te. In this work, we synthesized Te-doped PtBi$_{2-x}$Te$_{x}$ samples and thoroughly investigated the bulk superconductivity of selected single crystals with nominal composition PtBi$_{1.96}$Te$_{0.04}$, exhibiting the highest superconducting volume fraction of $\sim100$%. Single crystal XRD measurements confirm the centrosymmetric $P\overline{3}m1$ structure in our samples, whereas bulk superconductivity with a critical temperature of $T_\mathrm{c} \approx 2.4\,$K was observed in magnetization and specific heat measurements. The upper critical fields for two different orientations were determined as $H^{\parallel}_{\mathrm{c2}}(0)\approx 6.3\,$kOe for in-plane and $H^{\perp}_{\mathrm{c2}}(0)\approx 4.7\,$kOe for out-of-plane magnetic fields. Robust superconductivity was also found in resistance and point contact measurements, where the latter showed a slight enhancement of the critical temperature up to $T_\mathrm{c} \sim 3\,$K. Finally, ARPES measurements corroborate the centrosymmetric structure of our samples, showing a single surface termination and the absence of Fermi arcs.

cond-mat.supr-con↗

arXiv2025

Dissecting coupled orders in a terahertz-driven electron-doped cuprate

The interplay between superconductivity and charge density wave has often been studied from an equilibrium point of view. For example, using static tuning knobs such as doping, magnetic field and pressure, superconductivity can be enhanced or suppressed. The resulting effect on the co-existing charge density wave order, if any, is judged by variations in its ground state properties such as the ordering temperature or the spatial correlation. Such an approach can be understood as coordinated static displacements of two coupled order parameters within a Ginzburg-Landau description, evincing their interplay as either co-operative or competing but does not provide further microscopic information about the interaction. In order to assess such information, we dynamically perturb both orders from equilibrium and observe their coupling directly in the time-domain. We show that high-field multicycle terahertz pulses drive both the Higgs amplitude fluctuations of the superconducting order as well as collective fluctuations of the charge order in an electron-doped cuprate, resulting in characteristic third harmonic generation. A notable time delay is manifested between their respective driven dynamics. We propose that this may signify the important energy scale describing their coupling or imply a terahertz field-depinned charge density wave that destroys macroscopic superconductivity. Our work demonstrates a holistic approach for investigating coupled superconducting and charge density wave orders, which may shed novel light on their intertwined presence and widespread fluctuations in many classes of unconventional superconductors.

cond-mat.supr-con↗