First-principles predictions of the geometries and electronic structures of tungsten ditelluride nanoribbons

First-principles calculations are carried out to predict the structures and electronic properties of 2H- and Td-WTe2 nanoribbons with different termination edges. It is found that the 2H-WTe2 nanoribbon along the armchair direction and the Td-WTe2 nanoribbon along the X direction show semiconducting characters with tunable band gaps. The 2H-WTe2 nanoribbon along the zigzag direction and the Td-WTe2 nanoribbon along the Y direction show metallic characters.