First some background:
I manage a small IT Operations department, and recently our IT director hired a new helpdesk tech. This person is really good at their work, and they have really improved the productivity of the helpdesk folks. The only problem is that he is really sociable, and chatty; he will talk for quite some time to you about just anything. It can be very distracting, and it really disrupts my work, making it impossible to get in a state of flow and perform deep work.
I am an escalation point for him, so I told him if he needs immediate help on a ticket, he's more than welcome to ping me for help, but he needs to check with me via IM first to see if I'm available to help. I've asked him politely to not distract me with chit chat when I'm not in the break room. I've tried establishing boundaries in more stern ways, and even mentioning that the problem with idle chatter is that I have a really hard time focusing again after I context switched like this. I've asked him to not just walk into my office before checking whether I am a good stopping point. All to no avail.
How do you guys deal with chatty co-workers or employees? Have you ever been in a similar situation?