  Metal-insulator transitions in two dimensional materials represent a great
opportunity for fast, low energy and ultra-dense switching devices. Due to the
small energy difference between its semimetallic and semiconducting crystal
phases, phase transition in MoTe$_2$ can occur with an unprecedented small
amount of external perturbations. In this work, we used density functional
theory to predict critical strain and electrostatic voltage required to control
the phase transition of 3d and 4d metal doped MoTe$_2$. We found that small
doping contents dramatically affect the relative energies of MoTe$_2$ crystal
phases and can largely reduced the energy input to trigger the transition,
compared to pristine case. Moreover, the kinetics corresponding to the phase
transition in the proposed doped materials are several order of magnitude
faster than in MoTe$_2$. For example, we predict 6.3 \% Mn doped MoTe$_2$ to
switch phase under 1.19 V gate voltage in less than 1 $\mu$s with an input
energy of 0.048 aJ/nm$^3$. Due to the presence of dopant, the controlled change
of phase is often complemented with a change in magnetic moment leading to
multi-functional phase transition.
