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Electron localization in the strongly correlated organic systemκ−(BEDT−TTF)2Xprobed with nuclear magnetic resonanceC13−NMR
- Source :
- Physical Review B. 70
- Publication Year :
- 2004
- Publisher :
- American Physical Society (APS), 2004.
-
Abstract
- $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}X$ salts exhibit a wide range of properties from superconductivity to magnetic ordering. The phase diagram of this system has been understood as the competition between anti-ferromagnetic insulating behavior and superconductivity. The $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}X$ system has been well explained using a parameter, U/W, as well as the high ${T}_{c}$ cuprates. $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}{\mathrm{Cu}}_{2}{(\mathrm{CN})}_{3}$, however, behaved as an insulator without magnetic ordering. This salt cannot be described by the phase diagram described by the competition between superconductivity and magnetism. It is interesting to explore the nature of this insulating phase with an eye toward understanding the universal phase diagram of the $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}X$ system. Magnetic frustration due to the triangular spin lattice has recently been reported for $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}{\mathrm{Cu}}_{2}{(\mathrm{CN})}_{3}$ from $^{1}\mathrm{H}$-nuclear magnetic resonance (NMR) study. To investigate the insulating properties of this salt, we characterized it using $^{13}\mathrm{C}\text{\ensuremath{-}}\mathrm{NMR}$. In contrast to previous $^{1}\mathrm{H}\text{\ensuremath{-}}\mathrm{NMR}$ studies, at low temperatures, we observed line broadenings that were proportional to the hyperfine coupling constants, which suggested inhomogeous electron localization. We also observed antiferromagnetic fluctuations which, as is the case with other salts, intensified with decreasing temperature. To understand the electronic properties of $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}X$ system, in addition to the U/W, the electron localization effect from the relatively narrow bandwidth is important.
- Subjects :
- Superconductivity
Physics
Condensed matter physics
Magnetism
Condensed Matter Physics
Magnetic susceptibility
Electron localization function
Electronic, Optical and Magnetic Materials
Nuclear magnetic resonance
Condensed Matter::Superconductivity
Antiferromagnetism
Condensed Matter::Strongly Correlated Electrons
Cuprate
Strongly correlated material
Phase diagram
Subjects
Details
- ISSN :
- 1550235X and 10980121
- Volume :
- 70
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi...........d18db7a81d34397d7d423c42c1168aed
- Full Text :
- https://doi.org/10.1103/physrevb.70.060510