Non-Fermi-liquid behavior of the organic superconductor kappa-(BEDT-TTF)(4)Hg2.89Br8 probed by C-13 NMR

Article

关键词: BEDT-TTF;    ELECTRON CORRELATION;    STATE;    RELAXATION;    TRANSITION;    PRESSURE;    BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE;    (ET)4HG2.89BR8;    CONDUCTOR;   

DOI  :  10.1103/PhysRevB.81.212503

来源: SCIE

【 摘 要 】

An organic salt, kappa-(BEDT-TTF)(4)Hg2.89Br8 exhibits superconductivity at 4.3 K under ambient pressure suggesting non-Fermi-liquid (NFL) behavior just above T-c. Whereas most organic superconductors are controlled by the bandwidth in the half-filled electron system, this salt realizes a carrier doping away from the half-filled electron system as well as high-T-c cuprates. In order to investigate the origin of NFL behavior, we assessed C-13-NMR measurements in this salt and observed the antiferromagnetic fluctuation as same as in an organic antiferromagnet kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl with the gap structure. Application of pressure suppresses (T1T)(-1) and shifts its maximum to lower temperatures with (T1T)(-1) becoming constant above 2 GPa. These results suggest that applying pressure alters the electron system from NFL to FL state and that antiferromagnetic fluctuations contribute to the origin of NFL behavior.

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