%0 Journal Article
%T Magnetism and Pressure-Induced Superconductivity of Checkerboard-Type Charge-Ordered Molecular Conductor ¦Â-(meso-DMBEDT-TTF)2X (X = PF6 and AsF6)
%A Takahisa Shikama
%A Tatsuya Shimokawa
%A Sanguchul Lee
%A Takayuki Isono
%A Akira Ueda
%A Kazuyuki Takahashi
%A Akiko Nakao
%A Reiji Kumai
%A Hironori Nakao
%A Kensuke Kobayashi
%A Youichi Murakami
%A Motoi Kimata
%A Hiroyuki Tajima
%A Kazuyuki Matsubayashi
%A Yoshiya Uwatoko
%A Yutaka Nishio
%A Koji Kajita
%A Hatsumi Mori
%J Crystals
%D 2012
%I MDPI AG
%R 10.3390/cryst2041502
%X The metallic state of the molecular conductor ¦Â-( meso-DMBEDT-TTF) 2X (DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5- b][1,4]dithiin-2-ylidene)-5,6-dihydro-5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin, X = PF 6, AsF 6) is transformed into the checkerboard-type charge-ordered state at around 75¨C80 K with accompanying metal-insulator (MI) transition on the anisotropic triangular lattice. With lowering temperatures, the magnetic susceptibility decreases gradually and reveals a sudden drop at the MI transition. By applying pressure, the charge-ordered state is suppressed and superconductivity appears in ¦Â-( meso-DMBEDT-TTF) 2AsF 6 as well as in the reported ¦Â-( meso-DMBEDT-TTF) 2PF 6. The charge-ordered spin-gapped state and the pressure-induced superconducting state are discussed through the paired-electron crystal (PEC) model, where the spin-bonded electron pairs stay and become mobile in the crystal, namely the valence-bond solid (VBS) and the resonant valence bonded (RVB) state in the quarter-filled band structure.
%K superconductor
%K dimer state
%K checkerboard-type charge ordering
%K singlet state
%K valence bond solid
%K paired-electron crystal
%U http://www.mdpi.com/2073-4352/2/4/1502