Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 71: Ultrafast Phenomena
TT 71.1: Talk
Thursday, March 12, 2026, 09:30–09:45, HSZ/0103
Ultrafast control of competing FM and CDW orders in SmNiC2 — •Chandra V Kotyada1, Bhageerath Swaraj1, Amon. P Lanz1, Priyanka Yogi1, Amir.A Haghighirad2, Sofia. M Souliou2, Matthieu Le Tacon2, and Jure Demsar1 — 1JGU Mainz — 2KIT
SmNiC2 belongs to the rare-earth (R) transition-metal carbide family RNiC2, a unique class of intermetallic compounds that crystallize in the non-centrosymmetric orthorhombic CeNiC2-type structure and exhibit pronounced quasi-one-dimensional characteristics. Diffraction studies on SmNiC2 reveal an incommensurate charge-density-wave (CDW) modulation with wavevector (0.5, 0.5 + δ, 0) below TCDW ≈ 148 K. Upon lowering the temperature, a first-order phase transition into a ferromagnetic (FM) state occurs at TM ≈ 18 K, accompanied by a complete suppression of the CDW order.
Here, we apply optical pump-probe spectroscopy to investigate collective response in both symmetry-broken phases. Using CDW amplitude mode as a fingerprint of the CDW order, we then use the quench-pump-probe approach to track the dynamics of the photoinduced FM-to-CDW phase transition. We show that the buildup of the CDW after quenching the FM order is limited by the demagnetization time of 10 ps.