Pressure and temperature dependence of interlayer spin diffusion and electrical conductivity in the layered organic conductors κ-(BEDT-TTF) 2Cu[N(CN)2]X (X=Cl, Br)

Ágnes Antal, T. Fehér, Erzsébet Tátrai-Szekeres, Ferenc Fülöp, Bálint Náfrádi, László Forró, A. Jánossy

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Abstract

A high frequency (111.2-420 GHz) electron spin resonance study of the interlayer spin diffusion is presented in the conducting phases of the layered organic compounds, κ-(BEDT-TTF)2Cu[N(CN)2]X (κ-ET2-X), X=Cl or Br. The interlayer spin cross relaxation time Tx and the intrinsic spin relaxation time T2 of single layers are measured as a function of temperature and pressure. Spin diffusion is two dimensional in the high temperature bad-metal phase (i.e., electrons are confined to a single molecular layer for longer than T 2). The interlayer electron hopping frequency ν = 1/(2T x) decreases along the bad-metal to Mott insulator crossover and increases along the bad-metal to normal metal (or superconductor) crossover. The density of states (DOS) is determined from a comparison of Tx and the interlayer resistivity. In the bad-metal phase it is four to five times larger than the DOS calculated from the electronic structure neglecting electron correlations. In κ-ET2-X the DOS increases with pressure along the bad-metal to normal metal crossover. Results are compared with predictions of the dynamical mean field theory.

Original languageEnglish
Article number075124
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number7
DOIs
Publication statusPublished - Aug 8 2011

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Organic conductors
pressure dependence
interlayers
conductors
Metals
conductivity
temperature dependence
electrical resistivity
metals
crossovers
Temperature
Relaxation time
relaxation time
frequency hopping
Electron correlations
Mean field theory
Frequency hopping
electrons
cross relaxation
Electrons

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Pressure and temperature dependence of interlayer spin diffusion and electrical conductivity in the layered organic conductors κ-(BEDT-TTF) 2Cu[N(CN)2]X (X=Cl, Br). / Antal, Ágnes; Fehér, T.; Tátrai-Szekeres, Erzsébet; Fülöp, Ferenc; Náfrádi, Bálint; Forró, László; Jánossy, A.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 84, No. 7, 075124, 08.08.2011.

Research output: Contribution to journalArticle

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abstract = "A high frequency (111.2-420 GHz) electron spin resonance study of the interlayer spin diffusion is presented in the conducting phases of the layered organic compounds, κ-(BEDT-TTF)2Cu[N(CN)2]X (κ-ET2-X), X=Cl or Br. The interlayer spin cross relaxation time Tx and the intrinsic spin relaxation time T2 of single layers are measured as a function of temperature and pressure. Spin diffusion is two dimensional in the high temperature bad-metal phase (i.e., electrons are confined to a single molecular layer for longer than T 2). The interlayer electron hopping frequency ν = 1/(2T x) decreases along the bad-metal to Mott insulator crossover and increases along the bad-metal to normal metal (or superconductor) crossover. The density of states (DOS) is determined from a comparison of Tx and the interlayer resistivity. In the bad-metal phase it is four to five times larger than the DOS calculated from the electronic structure neglecting electron correlations. In κ-ET2-X the DOS increases with pressure along the bad-metal to normal metal crossover. Results are compared with predictions of the dynamical mean field theory.",
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AU - Antal, Ágnes

AU - Fehér, T.

AU - Tátrai-Szekeres, Erzsébet

AU - Fülöp, Ferenc

AU - Náfrádi, Bálint

AU - Forró, László

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N2 - A high frequency (111.2-420 GHz) electron spin resonance study of the interlayer spin diffusion is presented in the conducting phases of the layered organic compounds, κ-(BEDT-TTF)2Cu[N(CN)2]X (κ-ET2-X), X=Cl or Br. The interlayer spin cross relaxation time Tx and the intrinsic spin relaxation time T2 of single layers are measured as a function of temperature and pressure. Spin diffusion is two dimensional in the high temperature bad-metal phase (i.e., electrons are confined to a single molecular layer for longer than T 2). The interlayer electron hopping frequency ν = 1/(2T x) decreases along the bad-metal to Mott insulator crossover and increases along the bad-metal to normal metal (or superconductor) crossover. The density of states (DOS) is determined from a comparison of Tx and the interlayer resistivity. In the bad-metal phase it is four to five times larger than the DOS calculated from the electronic structure neglecting electron correlations. In κ-ET2-X the DOS increases with pressure along the bad-metal to normal metal crossover. Results are compared with predictions of the dynamical mean field theory.

AB - A high frequency (111.2-420 GHz) electron spin resonance study of the interlayer spin diffusion is presented in the conducting phases of the layered organic compounds, κ-(BEDT-TTF)2Cu[N(CN)2]X (κ-ET2-X), X=Cl or Br. The interlayer spin cross relaxation time Tx and the intrinsic spin relaxation time T2 of single layers are measured as a function of temperature and pressure. Spin diffusion is two dimensional in the high temperature bad-metal phase (i.e., electrons are confined to a single molecular layer for longer than T 2). The interlayer electron hopping frequency ν = 1/(2T x) decreases along the bad-metal to Mott insulator crossover and increases along the bad-metal to normal metal (or superconductor) crossover. The density of states (DOS) is determined from a comparison of Tx and the interlayer resistivity. In the bad-metal phase it is four to five times larger than the DOS calculated from the electronic structure neglecting electron correlations. In κ-ET2-X the DOS increases with pressure along the bad-metal to normal metal crossover. Results are compared with predictions of the dynamical mean field theory.

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