Prediction of low energy phase transition in metal doped MoTe$_2$ from first principle calculations

Abstract

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.