Antiferromagnetic ordering in organic conductor $\lambda$-(BEDT-TTF)${}_2$GaCl${}_4$ probed by ${}^{13}$C NMR

Abstract

The ground state of $\lambda$-(BEDT-TTF)${}_2$GaCl${}_4$, which has the same structure as the organic superconductor $\lambda$-(BETS)${}_2$GaCl${}_4$, was investigated by magnetic susceptibility and ${}^{13}$C NMR measurements. The temperature dependence of the magnetic susceptibility revealed an antiferromagnetic (AF) correlation with $J/k_{\mathrm{B}}\simeq$ 98 K. NMR spectrum splitting and the divergence of $1/T_1$ were observed at approximately 13 K, which is associated with the AF transition. We found that the AF structure is commensurate according to discrete NMR peak splitting, suggesting that the ground state of $\lambda$-(BEDT-TTF)${}_2$GaCl${}_4$ is an AF dimer-Mott insulating state. Our results suggest that the superconducting phase of $\lambda$-type salts would be located near the AF insulating phase.

arXiv comment5 pages, 4 figures

References in corpus (6)

• Pairing due to Spin Fluctuations in Layered Organic Superconductors
• Superconductivity mediated by charge fluctuations in layered molecular crystals
• Magnetic field - temperature phase diagram of quasi-two-dimensional organic superconductor lambda-(BETS)_2 GaCl_4 studied via thermal conductivity
• Superconducting phase diagram and FFLO signature in $\lambda$-(BETS)${}_2$GaCl${}_4$ from rf penetration depth measurements
• Charge-order fluctuations and superconductivity in two-dimensional organic metals
• On the Spin Gap Phase in lambda-(BETS)_2GaX_zY_{4-z}

Cited by in corpus (4)

• Electronic Structure Calculation and Superconductivity in $\lambda$-(BETS)${}_2$GaCl${}_4$
• Antiferromagnetic ordering of organic Mott insulator $\lambda$-(BEDSe-TTF)${}_2$GaCl${}_4$
• Charge imbalance in $\lambda$-(BETS)${}_2$GaCl${}_4$ and their interplay with superconductivity
• Dynamics of ethylene groups and hyperfine interactions between donor and anion molecules in $\lambda$-type organic conductors studied by ${}^{69,71}$Ga-NMR spectroscopy