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TT: Fachverband Tiefe Temperaturen
TT 80: Correlated Electrons: Poster
TT 80.39: Poster
Thursday, March 21, 2024, 15:00–18:00, Poster E
Interplay between the coupled electronic and lattice orders in unconventional CDW systems BaNi2As2 studied by collective mode spectroscopy — •Chandra Vardhan Kotyada1, Priyanka Yogi1, Amon P. Lanz1, Amrit R. Pokharel1, Amir A. Haghighirad2, Matthieu Le Tacon2, and Jure Demsar1 — 1Institute of Physics, Johannes Gutenberg University Mainz, 55128 Mainz, Germany — 2Institute for Quantum Materials and Technologies, KIT, 76344 Karlsruhe, Germany
Time-resolved reflectivity studies of in BaNi2As2, a non-magnetic analogue of the parent compound of a pnictide superconductor BaFe2As2, reveal the existence of several charge-density-wave (CDW) amplitude modes[1], as in prototype CDW systems[2]. Their temperature and excitation density dependence suggest the charge-order driven nematicity in BaNi2As2 and support the idea of orthorhombic-triclinic structural symmetry phase transition being mediated by the stabilization of the CDW order[1]. We extend our studies to cover a large range in P-substituted BaNi2(As1−xPx)2[3]. Beyond the triclinic critical point (x 0.07), where also six-fold enhancement of superconducting Tc is observed[3], only two strongly damped sub-THz amplitude modes are resolved. The fact that diffraction and spectroscopic data[3] imply the absence of orthorombic distortions in samples beyond x 0.07 suggests the changes in the collective mode spectrum may be linked to variation in nematicity.
[1] A.R. Pokharel et. al., Comm. Phys. 5, 141 (2022)
[2] K. Warawa et al., Phys. Rev. B 108, 045147 (2023)
[3] Y. Yao et al., Nat. Commun. 13, 4535 (2022)
Keywords: charge density wave (CDW); Collective mode spectroscopy; Phase transition; BaNi2As2