skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Antiferromagnetic fluctuations in a quasi-two-dimensional organic superconductor detected by Raman spectroscopy

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1223580
Grant/Contract Number:
FG02-08ER46544
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 92; Journal Issue: 16; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Drichko, Natalia, Hackl, Rudi, and Schlueter, John A. Antiferromagnetic fluctuations in a quasi-two-dimensional organic superconductor detected by Raman spectroscopy. United States: N. p., 2015. Web. doi:10.1103/PhysRevB.92.161112.
Drichko, Natalia, Hackl, Rudi, & Schlueter, John A. Antiferromagnetic fluctuations in a quasi-two-dimensional organic superconductor detected by Raman spectroscopy. United States. doi:10.1103/PhysRevB.92.161112.
Drichko, Natalia, Hackl, Rudi, and Schlueter, John A. Thu . "Antiferromagnetic fluctuations in a quasi-two-dimensional organic superconductor detected by Raman spectroscopy". United States. doi:10.1103/PhysRevB.92.161112.
@article{osti_1223580,
title = {Antiferromagnetic fluctuations in a quasi-two-dimensional organic superconductor detected by Raman spectroscopy},
author = {Drichko, Natalia and Hackl, Rudi and Schlueter, John A.},
abstractNote = {},
doi = {10.1103/PhysRevB.92.161112},
journal = {Physical Review B},
number = 16,
volume = 92,
place = {United States},
year = {Thu Oct 15 00:00:00 EDT 2015},
month = {Thu Oct 15 00:00:00 EDT 2015}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.92.161112

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

Save / Share:
  • Using Raman scattering, the quasi-two-dimensional organic superconductor kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br (T-c = 11.8 K) and the related antiferromagnet kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl are studied. Raman scattering provides unique spectroscopic information about magnetic degrees of freedom that has been otherwise unavailable on such organic conductors. Below T = 200 K a broad band at about 500 cm(-1) develops in both compounds. We identify this band with two-magnon excitation. The position and the temperature dependence of the spectral weight are similar in the antiferromagnet and in the metallic Fermi liquid. We conclude that antiferromagnetic correlations are similarly present in the magnetic insulator and the Fermi-liquid state ofmore » the superconductor.« less
  • The condensate pair fluctuations in the frequency region [omega][approx lt]2[Delta] and the associated Raman-scattering intensity of a two-dimensional (2D) [ital d]-wave weak-coupling BCS superconductor are investigated. Our model includes a dominant [ital d][sub [ital x]][sup 2][minus][ital y][sup 2] ([ital L]=2) and a weaker [ital s]-wave ([ital L]=0) pairing interaction. All response functions involving density and pair operators are evaluated (in the low-[bold q] limit). For neutral [ital d]-wave superconductors (no Coulomb interaction), the expected phononlike phase mode is obtained in the [ital L]=0 channel (which couples to density fluctuations). In contrast, excitonlike modes corresponding to excited Cooper pair states aremore » obtained in the [ital L]=2 channel. We find an amplitude fluctuation mode with frequency [radical]3 [Delta]. For charged [ital d]-wave superconductors, the [ital L]=0 phonon is renormalized into a 2D plasmon, but the [ital L]=2 excitonlike mode remains unaffected by the Coulomb interaction. At [ital T]=0, the latter is shown to be completely washed out in the Raman scattering spectrum ([bold q]=0) due to large [ital p]-[ital h] damping (which arises in the absence of a finite pair-breaking gap in [ital d]-wave superconductors). However, at finite temperatures, we find the energy of the excitonlike mode is drastically lowered [relative to 2[Delta]([ital T])] when the [ital s]-wave attraction is comparable to the [ital d]-wave pairing. This leads to a decrease in the damping and, as a result, the mode shows up as a low-frequency resonance in the Raman cross section. Due to the anisotropy of the [ital d]-wave order parameter, the quasiparticle excitation spectrum and the noninteracting two-particle spectrum are strongly dependent on the direction of [bold q]. We also find that the excitonlike mode frequency becomes anisotropic for wave vectors of the order of [Delta]/[ital v][sub [ital F]].« less
  • We have investigated experimentally and theoretically electronic Raman excitations in GaAs-Al{sub {ital x}}Ga{sub 1{minus}{ital x}}As quantum wires in magnetic fields. In both the experiments and the calculations we find strong anticrossings of the observed confined magnetoplasmon modes in the vicinity of 2{omega}{sub {ital c}}, where {omega}{sub {ital c}} is the cyclotron-resonance frequency. The observed splittings and anticrossings arise from internal Coulomb interaction in the one-dimensional electron systems and is found to depend sensitively not only on the wave vector but also on the shape of the confining potential and the mode index of the confined plasmon mode. {copyright} {ital 1996more » The American Physical Society.}« less
  • We have calculated the hopping conductivity of quasi-two-dimensional systems by using the variable-range hopping conduction mechanism in the presence of an electric field. We considered that the localized states are randomly distributed both in energy and space coordinates. Localized carriers hop from one state to another in both coordinates. We also considered that at a particular temperature the localized carriers are distributed according to the Fermi distribution function both below and above the Fermi level. The expression of the conductivity for the constant density of states was calculated. After some approximations, the expression of the conductivity was shown to reducemore » to expressions found in the literature. We also compared our theory with experimental results of PrBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital y}} based {ital S}/{ital N}/{ital S} junctions. Good agreement between theory and experiment was found. {copyright} {ital 1996 The American Physical Society.}« less