open access

https://hdl.handle.net/2115/57966

Thermopower analysis of the electronic structure around the metal-insulator transition in V1-xWxO2

英語

2014-10-21

American Physical Society

Physical review. B

90(16)

161105-1-161105-4

The electronic structure across the metal-insulator (MI) transition of electron-doped V1-xWxO2 epitaxial films (x = 0-0.06) grown on alpha-Al2O3 substrates was studied by means of thermopower (S) measurements. Significant increase of vertical bar S vertical bar values accompanied by MI transition was observed, and the transition temperatures of S (T-S) decreased with x in a good linear relation with MI transition temperatures. vertical bar S vertical bar values of V1-xWxO2 films at T > T-S were constant at low values of 23 mu VK-1 independently of x, which reflects a metallic electronic structure, whereas those at T < T-S almost linearly decreased with logarithmic W concentrations. The gradient of -213 mu VK-1 agrees well with -k(B)/e ln10 (-198 mu VK-1), suggesting that V1-xWxO2 films have insulating electronic structures with a parabolic density of state around the conduction band bottom.

学術雑誌論文

Version of Record

©2014 American Physical Society

1098-0121

1550-235X

AA11187113