Phonon softening and slowing down of charge-density-wave fluctuations in BaNi${}_2$As${}_2$

Abstract

BaNi${}_2$As${}_2$ is a nonmagnetic analogue of the iron pnictide superconductors, and in its tetragonal state exhibits an incommensurate charge-density-wave (IC-CDW) and a sizable elastoresistance. In this work, phonons in BaNi${}_2$As${}_2$ associated with the IC-CDW and uniform in-plane lattice distortions are investigated using high-resolution inelastic X-ray scattering. The in-plane transverse acoustic phonons reveal no softening at temperatures where the elastoresistance increases strongly, indicating the latter to be electronically driven. Systematic phonon measurements reveal the IC-CDW occurs in two stages upon cooling: underdamped phonons first soften to zero energy well above the IC-CDW ordering temperature, then the resulting quasielastic IC-CDW fluctuations gradually slow down and coalesce into the static IC-CDW order. A possible origin for our observations is the IC-CDW in tetragonal BaNi${}_2$As${}_2$ being uniaxial, which provides an additional Ising degree of freedom favorable for disordered IC-CDW modulations, and accounts for the elastoresistance through a weak coupling to the lattice.

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References in corpus (18)

• Classification of Charge Density Waves Based on Their Nature
• Nematic spin correlations in the tetragonal state of uniaxial strained BaFe2-xNixAs2
• First Order Phase Transition and Superconductivity in BaNi2As2 Single Crystals
• Structure and Anisotropic Properties of BaFe2-xNixAs2 (x = 0, 1, 2) Single Crystals
• Charge ordering in superconducting copper oxides
• Giant Phonon Softening and Enhancement of Superconductivity by Phosphorus Doping of BaNi2As2
• Multiple charge density waves and superconductivity nucleation at antiphase domain walls in the nematic pnictide Ba${}_{1-x}$Sr${}_x$Ni${}_2$As${}_2$
• Superconducting fluctuations in overdoped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$
• An Electronic Nematic Liquid in BaNi${}_2$As${}_2$
• Electronic structure of BaNi${}_2$As${}_2$
• Elastoresistivity in the incommensurate charge density wave phase of BaNi${}_{\text{2}}$(As${}_{\text{1-x}}$P${}_{\text{x}}$)${}_{\text{2}}$
• Soft-phonon and charge-density-wave formation in nematic BaNi${}_2$As${}_2$
• Rotational symmetry breaking at the incommensurate charge-density-wave transition in Ba(Ni,Co)${}_2$(As,P)${}_2$: Possible nematic phase induced by charge/orbital fluctuations
• Close correlation between magnetic properties and the soft phonon mode of the structural transition in BaFe${}_2$As${}_2$ and SrFe${}_2$As${}_2$
• Short-range nematic fluctuations in Sr1-xNaxFe2As2 superconductors
• Order-Disorder Transitions in (Ca${}_x$Sr${}_{1-x}$)${}_3$Rh${}_4$Sn${}_{13}$
• Soft elastic constants from phonon spectroscopy in hole-doped Ba${}_{1-x}$(K,Na)${}_x$Fe${}_2$As${}_2$ and Sr${}_{1-x}Na$_x$Fe$_2$As$_2$
• Complex structure due to As bonding and interplay with electronic structure in superconducting BaNi2As2

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• Charge Order Evolution of Superconducting BaNi2As2 Under High Pressure
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• Charge density waves and soft phonon evolution in the superconductor BaNi${}_2$(As${}_{1-x}$P${}_x$)${}_2$
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