Dresden 2026 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 23: Correlated Electrons – Poster I
TT 23.31: Poster
Montag, 9. März 2026, 18:00–20:00, P1
Collective dynamics in SmNiC2 probed by time resolved spectroscopy — •Priyanka Yogi1, Chandra V Kotyada1, Bhageerath Swaraj1, Amon. P Lanz1, Amir.A Haghighirad2, Sofia. M Souliou2, Matthieu Le Tacon2, and Jure Demsar1 — 1JGU Mainz — 2KIT
Rare-earth transition-metal carbides RNiC2 are a unique class of intermetallic compounds that crystallize in a non-centrosymmetric orthorhombic CeNiC2-type structure. Except for LaNiC2 and CeNiC2, where exotic superconductivity has been reported, most members of this family exhibit quasi-1D charge-density-wave (CDW) order and competing magnetic order at low temperature. SmNiC2 is unique, where an incommensurate CDW order appearing below TCDW ≈ 148 K gets fully suppressed below a first-order transition into a ferromagnetic (FM) phase at TM ≈ 18 K.
Here, we employ optical pump-probe spectroscopy to investigate the interplay between the FM and CDW phases by probing single-particle and collective dynamics as a function of temperature. The FM phase is characterized by rather slow (10 ps) demagnetization dynamics, while in the CDW phase, we observe characteristic CDW collective modes. The dominant amplitude mode is found at 1.45 THz, showing pronounced softening towards TCDW. Excitation density-dependent studies provide additional information on the strength of the two phases.