How to ask my former PhD supervisor to stay away from me and do not contact my prospective new PhD supervisor? There are a long list of stories about the issues with my PhD supervisor here in Academia.SE (see it here but these are not the only ones). So, I'm not going to repeat why I'm leaving my current research group. Last week, I decided to change my research group after almost 5 years. Despite its painful nature to switch after 5 years of work, I'm really hopeful that I can find a new PhD advisor who help me to finish my thesis and get my degree.
I was in the same situation of switching to a new research group in Fall 2019, but at that time, still I was not 100% confident that I will not be able to get my PhD degree with my current advisor. In fact, in Fall 2019, I left my current research group for a couple of months and searched for a new PhD advisor. The problem was that every time I reached to a professor, even in other departments, my current advisor sent an email to them and recommended them to not accept me as their student. At the end, when I realized that nobody wants to take me as his/her student, my current advisor requested to have a meeting with me and he said that we are in a really good shape in terms of research progress and I will be able to get graduated soon, which didn't happen at all.
Long story short, I reached the end of my capability to work with my current PhD advisor and even I don't want to see him or hear his voice again. I talked to our graduate coordinator in the department and he also said that I should change my research group and he supports my decision.
Tomorrow, I'm going to have a meeting with my current advisor as well as the chair of the department and graduate coordinator. Based on my discussion to our graduate coordinator, this meeting is going to be a formal briefing about what would happen when I switch to another research group. For example, who owns the data and intellectual property that are created during these 5 years, which I don't have any claim and I want to just accept their requests and do whatever they want me to do and just move on. My current concern is that my current advisor wants to repeat the same strategy to prevent other professors to take me as their student and after that again try to force me to back to his group, which even I prefer to switch to master degree but do not continue my PhD with him. I want to ask him politely tomorrow in front of chair of the department and graduate coordinator to stop sending email to prospective advisors that I would contact in the future, but I don't know how to do that. I really appreciate any help or suggestion.
It’s superbly clear: You are being manipulated by a person who possibly has wasted years of your life. At this point, everything they do must be presumed malicious and intentional. Don’t take any other explanations, that’ll be gaslighting. You have to treat your former advisor like a public enemy #1, and his every action must be from now on interpreted as being on a vendetta against you. Look at the last few years. Has that person ever done anything that actually helped you achieve your goals? Don’t think of positive things they said: have they actually been helpful, in the truest sense of the word? Has their helpfulness been of the genuine kind that helps you make progress in the project, or it was only of a kind to put your mind at ease and dismiss the previous horrible things that person has done? My guess: it’s solid NO, they never helped in the last couple of years, and you’re clearly dealing with a manipulator who has no qualms about anything they did so far.
Don’t ever believe any excuses they may offer to recast their abhorrent behavior in a good light. Remember how you felt through this whole ordeal and what a mess it was because of that person. There is no excuse for their behavior. None whatsoever. They are a lost cause in every sense of the word.
Some of the answers to your other related questions seemed to have been slightly equivocal or giving the whole matter some benefit of the doubt. Having had the dubious pleasure of dealing with people like the one you describe early in my life, all your recollections are stereotypical and there's no doubt in my mind that you have been taken advantage of and have been subject of gross mistreatment. The person you speak of is playing a game that takes cards from the same decks that many other such people use. The game they play is so typical and so highly stylized that it may as well be called chess. You see it once and you can't unsee it, pretty much.