Title: Role of Vanadyl Oxygen in Understanding Metallic Behavior of V2O5(001) Nanorods,
Abstract: Vanadium pentoxide (V2O5), the most stable member of vanadium oxide family,
exhibits interesting semiconductor to metal transition in the temperature range
of 530-560 K. The metallic behavior originates because of the reduction of V2O5
through oxygen vacancies. In the present report, V2O5 nanorods in the
orthorhombic phase with crystal orientation of (001) are grown using vapor
transport process. Among three nonequivalent oxygen atoms in a VO5 pyramidal
formula unit in V2O5 structure, the role of terminal vanadyl oxygen (OI) in the
formation of metallic phase above the transition temperature is established
from the temperature-dependent Raman spectroscopic studies. The origin of the
metallic behavior of V2O5 is also understood due to the breakdown of pdpi bond
between OI and nearest V atom instigated by the formation of vanadyl OI
vacancy, confirmed from the downward shift of the bottom most split-off
conduction bands in the material with increasing temperature.