Speaker
Description
We report the discovery of a remarkably rich phase diagram in the kagome superconductor YRu$_{3}$Si$_{2}$, uncovered through a unique combination of muon spin rotation, magnetotransport, X-ray diffraction, and density functional theory calculations. Our study reveals the emergence of a charge-ordered state with a propagation vector of (1/2, 0, 0), setting a record onset temperature of 800 K for such order in a kagome system and for quantum materials more broadly. In addition, we observe time-reversal symmetry breaking below $T_{2}^{*}$ ${\simeq}$ 30 K and field-induced magnetism below $T_{1}^{*}$ ${\simeq}$ 80 K, indicating the presence of a hidden magnetic state. These transitions are mirrored in the magnetoresistance data, which show a clear onset at 100 K and a pronounced increase below 30 K, ultimately reaching a maximum magnetoresistance of 45${\%}$. Band structure calculations identify two van Hove singularities near the Fermi level, one of which resides within a flat band, suggesting a strong interplay between electronic correlations and emergent orders. At low temperatures, we find bulk superconductivity below $T_{\rm c}$ = 3.4 K, characterized by a two-gap (s+s)-wave or anisotropic s-wave pairing symmetry. Together, our findings point to a coexistence of high-temperature charge order, tunable magnetism, and multigap superconductivity in YRu$_{3}$Si$_{2}$, positioning it as a compelling platform for exploring strongly correlated kagome physics.
| petr.kral@psi.ch | |
| Funding Agency | Swiss National Science Foundation |
| Supervisors Name | Zurab Guguchia |
| Supervisors Email | zurab.guguchia@psi.ch |
| Did you request an Invitation Letter for a Visitors Visa Application | No |
