Don't leave your job. You appear to be working for a good company with lots of potential opportunities. I get the impression that your manager might be protect

Don't leave your job. You appear to be working for a good company with lots of potential opportunities. I get the impression that your manager might be protecting your under-performing coworker. So I suggest a two step approach: 1. Go to your manager, explain that out of your team of N persons, all but one work well with you and you with them. Request that somebody else work with the one coworker that you have problems with. If your manager refuses, then: 2. Go to HR or your manager's manager and explain that you are working well with your team and only having conflict with one coworker, who in your assessment is under-performing and for reasons unknown to you the issue isn't being addressed by your immediate manager. Thus ask to be assigned to a different team within the company or if no such position is immediately open, to be relieved of working with the errant coworker.