In Book - Deep Work.. 3 Rules for Focused Success in a Distracted World, Adam Grants work habits are explored. One of them sounds odd, but could be very effective: He uses out of office email notifications even though he is in the office. This notifies everyone that he will spent the current time fully focused on a single deep task.
This idea is a stronger version of Checking emails only twice a day is an easy way to improve productivity
(Doing so might also improve the productivity of the entire department, as he is openly advertising his method of work to all of his colleagues)