Incoherent interplane conductivity ofκ−(BEDT−TTF)2Cu[N

Abstract

The interplane optical spectrum of the organic superconductor -(BEDT-TTF) 2 Cu͓N(CN) 2 ͔Br was investigated in the frequency range from 40 to 40 000 cm Ϫ1 . The optical conductivity was obtained by Kramers-Kronig analysis of the reflectance. The absence of a Drude peak at low frequency is consistent with incoherent conductivity but in apparent contradiction to the metallic temperature dependence of the dc resistivity. We set an upper limit to the interplane transfer integral of t b 2 /t ac Ϸ10 Ϫ7 eV. A model of defect-assisted interplane transport can account for this discrepancy. We also assign the phonon lines in the conductivity to the asymmetric modes of the BEDT-TTF molecule.

Bandwidth-controlled Mott transition inκ−(BEDT−TTF)2Cu[N(C<

“…The absolute values of reflectivity and conductivity are slightly enhanced compared to previously published results. 15,17,18,19,20,21 This we attribute to our advanced in-situ gold-evaporation method for the reference measurement which also accounts for imperfections of the crystal surface.…”

“…15,16,17,18,19,20,21 They gave a general idea of the electronic excitation observed in the infrared region: a broad mid-infrared band around 2500 − 3500 cm…”

Spin and Charge Transport in the X-ray Irradiated Quasi-2D Layered Compound: κ-(BEDT-TTF)2Cu[N(CN)2]Cl

“…The in-plane resistivity is assumed to be small and without any effect on ρ ⊥ . A defect-assisted interplane conductivity has also been proposed [15] to explain the metallic zero frequency interplane conductivity and the absence of a Drude peak in the optical conductivity in κ-ET 2 -Br. However, it is difficult to understand within this model the irradiation and temperature independence of the anisotropy between 50 and 250 K in κ-ET 2 -Cl.…”

Effect of superconducting fluctuations on ultrasound in an unconventional superconductor

“…Such a high anisotropy can raise the issue of incoherent electron motion in the perpendicular, z-direction. [22,23] In the case of weakly incoherent interlayer motion, [23] the intralayer electron momentum is conserved in the tunneling process and the electron wave function in adjacent layers has some overlap, but there are many in-plane collisions between tunneling events. In this case as well as for coherent interlayer motion, the use of the quasiparticle spectrum Eq.…”