SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 5: Poster Session: Superconductivity
TT 5.11: Poster
Montag, 27. September 2021, 13:30–16:00, P
Anomalous softening of phonon-dispersion in the under-doped cuprate superconductors — •Saheli Sarkar1,2, Maxence Grandadam1, and Catherine Pépin1 — 1Institut de Physique Théorique, Gif-sur Yvette, France — 2Current affiliation: Institut für QuantenMaterialien und Technologien, Karlsruhe Institute of Technology, Karlsruhe, Germany
Cuprate superconductors possess a complex phase diagram with various other phases like charge density wave (CDW) in the underdoped region. Interestingly, the CDW order has become fundamentally important due to growing evidences of its close relation to the pseudo-gap phase. One leading approach to unravel the relation, is to study the phonon-spectrum which couples to electronic degrees of freedom, thus leaving fingerprints associated with the electronic-structure. Several experiments have observed a softening of the phonon-dispersion in the underdoped cuprates at the CDW ordering wave vector, but only below the superconducting transition temperature. The phonon-softening in cuprates is considered `anomalous' since it is in sharp contrast to the situation in metallic systems where such softening occurs for temperatures below the onset of CDW order. By employing a perturbative approach, we find that a complex interplay among the CDW order, superconductivity and a finite quasi-particle lifetime arising from an unusually connected thermal fluctuations of these orders, can explain the `anomalous' nature of the phonon-softening, also giving good accounts for other features observed in recent inelastic-Xray scattering experiments.