title: Quantum phase transition in organic charge-transfer complexes.
abstract: A phase transition in an organic charge-transfer complex, which originates from the neutral-ionic valence instability, can be tuned toward zero kelvin with use of external pressure or chemical modification as a control parameter. The phase diagram and observed dielectric behaviors are typical of quantum paraelectricity, yet this zero-kelvin transition point namely, the quantum critical point, accompanies large quantum fluctuation of the molecular charge, as demonstrated by the molecular vibrational mode spectra. The result indicates that the pi-electron transfer between donor and acceptor molecules is coupled with the zero-point lattice dynamics around the quantum critical point.
authors.affiliation: Correlated Electron Research Center (CERC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8562, Japan. s-horiuchi@aist.go.jp
authors.forename: Sachio
authors.initials: S
authors.lastname: Horiuchi
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Okimoto
authors.forename: Reiji
authors.initials: R
authors.lastname: Kumai
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tokura