Structure cristalline d'un conducteur métallique bidimensionnel: Le bronze violet de potassium et molybdene K0.9Mo6O17

Band structure of the quasi two-dimensional purple molybdenum bronze

“…Therefore the crystal structure of KMo 6 O 17 presents distorted MoO 6 octahedra and MoO 4 tetrahedra and the XANES results corroborate the crystal structure shown in the Fig. 2 [3].…”

“…Most of the electronic properties show a large two-dimensional (2D) anisotropy, in relation with the layered crystallographic structure. This structure, with a trigonal symmetry, consists in staking MoO 6 octahedra infinite layers, bordered by two planes of MoO 4 tetrahedra, and separated by a plane of potassium [3]. The confinement of the conduction electrons in the middle of the octahedra layers, parallel to the (0 0 1) plane, makes this bronze twodimensional.…”

Discovery of an Unconventional Charge Density Wave at the Surface ofK0.9Mo6O17Mou1, Sapkota2, Kung3 et al. 2016Phys. Rev. Lett.293220View full textAdd to dashboardCite

“…The K 0.9 Mo 6 O 17 compound crystallizes in a trigonal structure belonging to the D 3i point group (space group P3, No. 147) [43]. The structure allows a total of 48 phonon modes at the Brillouin zone center (Γ point), categorized by the irreducible representations of the D 3i group: A u + E u acoustic modes, 13A u + 13E u infrared active optical phonons, and 10A g + 10E g Raman active phonons.…”

“…K 0.9 Mo 6 O 17 belongs to a family of materials including both one dimensional (1D) and two dimensional (2D) systems [41] and has been regarded as a model quasi-2D CDW material with T B CDW ∼ 115 K [42]. Its crystal structure [43] consists of a stacking of molybdenumoxygen slabs (Mo 6 O 17 ) along the hexagonal c axis with potassium atoms intercalated between these slabs. The Mo-O layers consist of Mo 2 O 10 zigzag chains along three directions, and the 2D Fermi surface (FS) can be constructed by superimposing three sets of quasi-1D FS lines, with a weak hybridization.…”

Magneto-optical properties ofLi0.9Mo6O17: Color change in applied magnetic field

“…The Li compound displays a quasi-one-dimensional metallic response at high temperature, a localization-induced upturn in the resistivity at 25 K, and a superconducting transition at 1.9 K. 14-18 The low-temperature resistivity increases in an applied field to at least 8 T. 19 The Na, K, and Tl analogs are all well-known two-dimensional charge density wave materials. 16,[20][21][22] In contrast, quasi-one-dimensional Li 0.9 Mo 6 O 17 seems to be dominated by localization effects, 23 which allows the density of states near the Fermi level to remain stable in spite of the metal-nonmetal transition. 23,24 Li purple bronze was selected for this work because of its quasi-one-dimensional transport properties, well-studied electronic structure, and finite lowtemperature density of states at the Fermi level.…”