Metal-semiconductor transition and Luttinger-liquid behavior in quasi-one-dimensionalBaVS3studied by photoemission spectroscopy

Abstract

binding energy, indicating that conduction electrons in BaVS3 behave as a Luttinger liquid. The powerlaw exponent is large ( & -1), indicating that electron-electron interaction is long ranged and possibly that electron-phonon interaction is also important. The spectra exhibit gradual changes with temperature. In particular, a semiconducting gap starts to open well above the metal-to-semiconductor transition temperature and fully develops below it. We propose that the gradual orthorhombic distortion of the Jahn-Teller type below -240 K lowers one of the d levels, d"~, and that below -70 K electrons are fully transferred to the d""band. The d"~b and then becomes half-filled, resulting in the opening of a Mott-Hubbard gap.

Dynamical correlation functions of one-dimensional superconductors and Peierls and Mott insulators

“…Their low-energy physics, therefore, can again be described by a Luther-Emery model, and our theory can be adapted to study the spectral functions of 1D Mott insulators. Earlier, angle-integrated photoemission on BaV S 3 has been interpreted as evidence for a Luttinger liquid 16 . The behavior of the conductivity, however, is more insulator-like, and present theory might be of interest there, too.…”

Orbitally driven spin pairing in the three-dimensional nonmagnetic Mott insulatorBaVS3:Evidence from single-crystal studies

“…The high temperature phase is a strongly correlated metal with mean free path in the order of the lattice constant. There is no sign of a sharp Fermiedge in the UPS/XPS spectra [6] and instead of a Pauli-susceptibility it exhibits Curie-Weiss like behavior. Though the magnetic susceptibility is similar to that of an antiferromagnet [10,11], no long-range magnetic order develops at the transition [9,12].…”

“…In contrast, the metal-insulator transition of the S = 1/2, 3d 1 electron system BaVS 3 is not associated either with magnetic long range order, or with any detectable static spin pairing. As an alternative, the possibility of an orbitally ordered ground state was discussed [4], while other proposals emphasized the quasione-dimensional character of the material [5][6][7]. The crystal structure is certainly suggestive of a linear chain compound since along the c axis, the intrachain V-V distance is only 2.81Å, while in the a-b plane the interchain separation is 6.73Å [8,9].…”

Structural aspects of the metal-insulator transition in BaVS3

“…BaVS 3 is a quasi-1D metal which exhibits anomalous electronic and magnetic properties [4][5][6][7][8] . Furthermore, BaVS 3 has a unique electronic structure.…”