Can We name new born baby “wahab” instead of Abdul Wahab”? Please give logical reason.

Yes, you can. Most of the names of God can be used as baby names, the most common of which is Ali, which is a name of God, and is also the name of Ali bin Abi Talib, the Prophet's cousin and the fourth Caliph, peace and blessing of God upon the Prophet and his family and companions.

For a list of names of God that cannot be used as baby names see: List of names of Allah prohibited for use as baby names