How to unbind tab key?

[ChillarAnand]

After installing zsh-autocomplete, tab is binded to menu-complete command. However, I want to use tab for zsh default autocompletion.

For example after typing cd <tab> should show cycles through directories.

How to achieve that?

I tried the following but that doesn't seem to work.

bindkey '^I'   complete-word       # tab          | complete
bindkey '^ ' complete-word
bindkey '       ' complete-word