  Twist between neighboring layers and variation of interlayer distance are two
extra ways to control the physical properties of stacked two-dimensional van
der Waals materials without alteration of chemical compositions or application
of external fields, compared to their monolayer counterparts. In this work, we
explored the dependence of the magnetic states of the untwisted and twisted
bilayer 1T-VX$_2$ (X = S, Se) on the interlayer distance by density functional
theory calculations. We find that, while a magnetic phase transition occurs
from interlayer ferromagnetism to interlayer antiferromagnetism either as a
function of decreasing interlayer distance for the untwisted bilayer 1T-VX$_2$
or after twist, richer magnetic phase transitions consecutively take place for
the twisted bilayer 1T-VX$_2$ as interlayer distance is gradually reduced.
Besides, the critical pressures for the phase transition are greatly reduced in
twisted bilayer 1T-VX$_2$ compared with the untwisted case. We derived the
Heisenberg model with intralayer and interlayer exchange couplings to
comprehend the emergence of various magnetic states. Our results point out an
easy access towards tunable two-dimensional magnets.
