arXiv subjects

John Schlueter

Publications and source records attributed to John Schlueter.

2 recordsLinked to original sources

arXiv2019

Evidence for a quantum dipole liquid state in an organic quasi-two-dimensional material

Mott insulators are commonly pictured with electrons localized on lattice sites. Their low-energy degrees of freedom involve spins only. Here we observe emerging charge degrees of freedom in a molecule-based Mott insulator $κ$-(BEDT-TTF)$_2$Hg(SCN)$_2$Br, resulting in a quantum dipole liquid state. Electrons localized on molecular dimer lattice sites form electric dipoles that do not order at low temperatures and fluctuate with frequency detected experimentally in our Raman spectroscopy experiments. The heat capacity and Raman scattering response are consistent with a scenario where the composite spin and electric dipole degrees of freedom remain fluctuating down to the lowest measured temperatures.

cond-mat.str-el↗

arXiv2003

Anomalous behaviour of the in-plane electrical conductivity of the layered superconductor $κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$

The quasiparticle scattering rates in high-quality crystals of the quasi-two-dimensional superconductor $κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$ ~are studied using the Shubnikov-de Haas effect and MHz penetration-depth experiments. There is strong evidence that the broadening of the Landau-levels is primarily caused by spatial inhomogeneities, indicating a quasiparticle lifetime for the Landau states $\gg 3$ ps. In contrast to the predictions of Fermi-liquid theory, the scattering time derived from the intralayer conductivity is found to be much shorter ($0.14-0.56$ ps).

cond-mat.str-el↗