# Stoichiometry Ratio and Tight-binding Model

#### gerryliyana

Is Stoichiometry ratio important in tight-binding approximation ?

i am going to calculate energy band structure of Vanadium dioxide using this approximation, so i have to determine its unit cell first (the unit cell of VO2 is shown at Fig 1).

(Figure 1. tetragonal unit cell of the high temperature phase of vanadium dioxide)

Because of some reasons, i decided to simplify that unit cell with considering only 110 surface, but a simplified unit cell that i made became non-stoichiometric (looks like VO). The simplified unit cell shown below.

(Figure 2. black = vanadium, blue = oxygen)

Is that permitted ??

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