Possible observation of the signature of the bad metal phase and its crossover to a Fermi liquid in Κ-(BEDT-TTF)2Cu(NCS)2bulk and nanoparticles by Raman scattering

Marco Revelli; Pierre Hemme; Yann Gallais; A Sacuto; Kane Jacob; Lydie Valade; Dominique De Caro; Christophe Faulmann; Maximilien Cazayous

doi:10.1088/1361-648X/abd813

Possible observation of the signature of the bad metal phase and its crossover to a Fermi liquid in Κ-(BEDT-TTF)₂Cu(NCS)₂bulk and nanoparticles by Raman scattering

J Phys Condens Matter. 2021 Jan 4. doi: 10.1088/1361-648X/abd813. Online ahead of print.

Authors

Marco Revelli¹, Pierre Hemme¹, Yann Gallais², A Sacuto¹, Kane Jacob³, Lydie Valade³, Dominique De Caro⁴, Christophe Faulmann⁴, Maximilien Cazayous⁵

Affiliations

¹ Paris University, 10 rue Alice Domon et Léonie Duquet, Paris, Île-de-France, 75013, FRANCE.
² Laboratoire Matériaux et Phénomenes Quantiques, Université Paris Diderot-Paris 7, Bâtiment Condorcet, Paris, 75205, FRANCE.
³ Coordination and chemistry laboratory, 205 Route de Narbonne, Toulouse, 31400, FRANCE.
⁴ Coordination and Chemistry Laboratory, 205 Route de Narbonne, Toulouse, 31400, FRANCE.
⁵ Paris University, 10 rue Alice Domon et Léonie Duquet, Paris, 75013, FRANCE.

PMID: 33395675
DOI: 10.1088/1361-648X/abd813

Abstract

Κ-(BEDT-TTF)₂Cu(NCS)₂has been investigated by Raman scattering in both bulk and nanoparticle compounds. Phonon modes from 20 to 1600 cm^-1have been assigned. Focusing on the unexplored low frequency phonons, a plateau in frequencies is observed in the bulk phonons between 50 and 100 K and assigned to the signature of the bad metal phase. Nanoparticles of Κ-(BEDT-TTF)₂Cu(NCS)₂exhibit anomalies at 50 K associated to the crossover from a bad metal to a Fermi liquid whose origins are discussed.

Keywords: Raman; organics; phonons.