I got my MS in mathematics 6 months earlier and now enrolled in a PhD program. But thinking to quit/take a break for at least a year. So, do you think I can apply for a full time job in USA being an international student? Also, will I be eligible to get the work authorization in USA? Thanks for your time good people.
Assuming that you're on a F-1 visa and you are already taking full time classes for your PhD, you cannot stop school and work full time while maintaining your F1 visa.
You have then 2 options:
1) Follow the F-1 regulations for employment while attending school. That is, work on campus, CPT or Pre-OPT. All options are very restrictive in terms of options and amount of work you can do.
2) Leave school and have an employer sponsor a work visa (e.g. H1-B, EB-2, etc.). This will allow you to work full time, however, given the amount of work necessary to get these petitions approved, I find unlikely that someone would hire you for only a year. In addition, if you do get one of these visas, you would want to pursuit your green card first before trying to be a full time student again.