Thermal switch based on ferroelasticity V^A-N binary compounds

Ferroelastic materials possess two or more equally stable orientation variants and can be effectively modulated via external fields, including stress and electronic field. In this paper, taking the V-A-N ferroelastic materials as examples, we propose a thermal switch device based on their ferroelastic characteristics. The results show that the V-A-N binary compound exhibits excellent ferroelasticity, high reversible elastic strain (5.5%-54.1%), and suitable switching energy barriers (0.012-0.386 eV/atom) in both d and a phases. Utilizing the advanced on-the-fly machine learning potential, we obtain physically well-defined quadratic dispersion curves in the long-wavelength limit and further evaluate their lattice thermal conductivity of d and a phase V-A-N binary compounds. Due to the difference in phonon group velocities, the lattice thermal conductivity of V-A-N binary compounds along the armchair direction is obviously smaller than that along the zigzag direction. Such remarkable anisotropy and easily switchable features based on ferroelasticity endow reversible and real-time regulation of thermal conductivity of V-A-N binary compounds. The ferroelastic-based thermal switch hosts high switch ratios range from 2.08 to 5.99 and does not require additional energy to maintain the modulation state. The results presented herein provide a pavement for designing next-generation thermal switches and propose a reliable solution for eliminating the nonphysical pseudo-phenomenon of phonon dispersion curve violation of quadratic dispersion in the long-wavelength limit.