Authors:	Pokharel, Amrit Raj Grigorev, Vladimir Mejas, Arjan Dong, Tao Haghighirad, Amir A. Heid, Rolf Yao, Yi Merz, Michael Le Tacon, Matthieu Demsar, Jure
Title:	Dynamics of collective modes in an unconventional charge density wave system BaNi2As2
Online publication date:	31-Oct-2022
Year of first publication:	2022
Language:	english
Abstract:	BaNi2As2 is a non-magnetic analogue of BaFe2As2, the parent compound of a prototype pnictide high-temperature superconductor, displaying superconductivity already at ambient pressure. Recent diffraction studies demonstrated the existence of two types of periodic lattice distortions above and below the triclinic phase transition, suggesting the existence of an unconventional charge-density-wave (CDW) order. The suppression of CDW order upon doping results in a sixfold increase in the superconducting transition temperature and enhanced nematic fluctuations, suggesting CDW is competing with superconductivity. Here, we apply time-resolved optical spectroscopy to investigate collective dynamics in BaNi2As2. We demonstrate the existence of several CDW amplitude modes. Their smooth evolution through the structural phase transition implies the commensurate CDW order in the triclinic phase evolves from the high-temperature unidirectional incommensurate CDW, and may indeed trigger the structural phase transition. Excitation density dependence reveals exceptional resilience of CDW against perturbation, implying an unconventional origin of the underlying electronic instability.
DDC:	530 Physik 530 Physics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 08 Physik, Mathematik u. Informatik
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-8164
Version:	Published version
Publication type:	Zeitschriftenaufsatz
Document type specification:	Scientific article
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	Communications Physics 5
Pages or article number:	141
Publisher:	Springer Nature
Publisher place:	London
Issue date:	2022
ISSN:	2399-3650
Publisher DOI:	10.1038/s42005-022-00919-x
Appears in collections:	DFG-491381577-G