Band electronic structure study of the electronic instability in the Magneli phase molybdenum oxide [Mo4O11]

Transient Thermoelectric Effect in Quasi‐Two‐Dimensional η‐Mo4O11 Crystal

“…In these materials, both electrons and holes contribute to the conduction process and various transport properties show anomalies near the CDW transition temperatures T,, GZ 105 K and E2 35 K for q-Mo,O,, and T,, = 100 K for y-Mo,O,, [2 to 61, in good agreement with the theoretical predictions by recent band calculations using a tight-binding approximation [7].…”

“…According to the band model for q -M o 4 0 , , in the normal state proposed recently by Canadell et al [7], there exist various electron and hole pockets in the Brillouin zone; electron pockets at the r point and along the Z-M direction, and hole pockets at the Z and Y points of the Brillouin zone. When the crystal enters the CDW states ( T < T,, and T',), the band structures may be changed appreciably by nesting of the Fermi surfaces of these carriers and the remaining electron or hole pockets are responsible for the thermal diffusion, as is observed.…”

Fermi-surface analysis of a quasi-two-dimensional monophosphate tungsten bronze

“…In the 1980s, Whangbo and co-workers performed theoretical tightbinding band calculations based upon the extended Hückel method. [9][10][11][12] From these studies they showed that the essential features of the MPTB electronic structure can be explained from ideal W 4 O 16 step layer calculations. Because this step layer is common to all the compounds of the MPTB family, the electronic structure is very similar in all these materials.…”

“…[9][10][11][12] When the calculations are performed taking into account the real distortion suffered by the WO 3 octahedra ͓see Fig. 2͑a͔͒, the double degeneration of the upper b band is lifted in bands b and c. The dispersive nature of these bands is due to the interaction between the W 4 O 18 chains and indicates the two-dimensional character of these bands.…”

“…In the particular case of the MPTB family members where pϭqϭmр6, the CDW phase transition is theoretically explained by the hidden-nesting mechanism. 8 This model [9][10][11][12] describes the FS as a superimposition of different sheets related to the onedimensional ͑1D͒ chains that form the MPTB structure. The CDW instabilities detected in these materials would be the result of the different nesting wave vectors associated with these 1D chains.…”