I recently graduated with a PhD in Fall 2022. In my PhD study, I published 7 papers in peer review journals and conferences. In summer semester of 2022, my PhD supervisor stopped my fund few days before the start of the semester and he claimed that I did bad in the previous semester. Later, he said I stopped your fund because you behaved improperly with me. The problem is that he requested me to work all the summer semester on non-research work in his lab such as revising his papers (I am not co-author in these papers) and train his team members with NO SALARY. I couldn't refuse because he wouldn't allow me to graduate. I want to send formal complaint against him to the university. When I told him that I am going to complain about that, he said many student are working on campus with no salary. I would like to know if his situation is illegal or not so that I make complaint against him.
You are asking an interesting question, but, not knowing the exact details and not being a lawyer, I cannot answer it for your case. It sounds to me that your relationship with your now ex-advisor broke down already before summer.
While most professors (including me) like to make jokes about having graduate students as slaves and cheap labor, they actually deeply care about their graduate students. I hope this includes me as well. The relationship between advisors and students often transcend a strict supervisor-employee relationship and sometimes gets closer to that of a family member (in part because the advisor is also supposed to be a mentor). This gives ample room for difficulties and misbehaviors if things "do not work out".
Belonging to a lab also takes on aspects of being a member of a family. It is typical that students that belong to a lab need to do work for the benefit of the lab, including some mentoring / training of new lab members. If it were the case that you did not do that before the summer, then it would seem just that you were asked to do it in the summer. Lab members are also expected to review other lab members publications. Again, if it were the case that you did not do this before the summer, then it would be fair to ask you to do some of this during your last summer. In addition, working on articles usually gives you ideas for new work of your own.
Now, a professor who does consider graduate students as some sort of indentured servant and gains personal profit from it is violating academic custom, their contract with the university, and the law. In this order, the chair, the dean, and the university's legal department should be the addressees of a complaint. Sometimes, there is a position such as a graduate student ombudsman that serves as a honest broker. When you complain, you should be clear on what you want to achieve. If you were doing forced labor, you could look for just compensation. If you were mistreated, you could look for an apology by the university and a prevention from this happening again. You could also of course find a lawyer (if you cannot find on, then you have no case) and use the courts directly. Going directly to the courts would make it difficult for you to find a job in academia.
As human beings, we all have a difficult time to separate emotions from facts. Maybe you should talk to your lab-mates or to previous graduate students. Whether there is a pattern of mistreatment of graduate students or not will make a lot of difference in how others will see your situation.
TLTR: Whether you were treated illegally cannot be determined by the data you provided us.
You really have to look at your contract with the university. In the US there is no standard grad student contract. For example, some universities have a policy that the admin guarantees grad student salaries for 9 months, but that summers are discretionary, and if the advisor decides to pay, it must be out of his/her own grants. Other universities guarantee 2 years of salary, but after that your salary is contingent on teaching every semester, which in practice means no summer salary. The teaching itself can be furthermore guaranteed (as in you are guaranteed a teaching slot) for 2-3 more years, but after that, you have to scavenge for teaching gigs within the university.
The system makes it very easy to abuse and exploit grad students. An unscrupulous professor will use the thesis sing-off as leverage to exploit graduate students for free labor. In terms of legality: in many (most?) places graduate students are not even considered employees, as you are supposedly getting trained and given free tuition, which is just an accounting trick. So employment laws do not apply, e.g. you can't get unemployment insurance payments during summers, you don't have the usual (however minimal) protections of employees in the US, etc. If you go to HR, I bet the case will be bumped to the department chair.
From the information you provide and without reading your contract, my best bet is this: unethical yes, illegal no.
I think there are two questions at play:
Was what your advisor did illegal?
- There is no way anyone here can give a good answer (you would need to find a lawyer).
Can you file a complaint?
- You can certainly file a complaint with the university/department or even your state's labor board. Whether this will result in any action is another issue, but illegality is not a prerequisite for raising the issue with the appropriate higher-ups. In fact, legality is almost irrelevant to academic ethics in many contexts.
To be honest, mentoring juniors is a usual task, and you can fit them into your own projects, with or without giving them co-authorships. Also, many research assistants, paid or not, are not entitled to a co-authorship. For example, in economic science, political science, and social sciences, paid research assistants are usually not coauthoring, but still doing a lot of work.
You could check the official website of journals like Nature to get an idea of what is a co-authorship. Revising or proof-reading a paper alone does not usually grant co-authorship.
You can always argue for your co-authorship, though. If it is in natural science, I think it cost your advisor little to add you as the sixth author. I suggest you to friendly, openly, and respectfully express your needs before battling with your advisor. You can also write your own papers without putting your advisor's name: this is reciprocity.