It looks like the Robot Mono fonts from nerd-fonts:

• https://github.com/ryanoasis/nerd-fonts/raw/master/patched-fonts/RobotoMono/complete/Roboto%20Mono%20Nerd%20Font%20Complete%20Mono.ttf

adds a lot of space compared to e.g. the one provided by google at:

• https://github.com/google/fonts/raw/master/apache/robotomono/RobotoMono-Regular.ttf.

See the following screen shots comparing them:

• From google:
  

• From nerd-fonts: