Martensitic transformation-assisted large thermal conductivity switching in Mn2V2O7 crystals

Materials that can switch between low and high thermal conductivity states enable on-demand management of temperature and heat flow, which will advance the application of solid-state refrigeration, energy conversion, and thermal circuits. Here, we report a large thermal conductivity on/off ratio of ∼1.49, accompanied by a martensitic transformation in Mn2V2O7 crystals at 290 K. This large on/off ratio in the thermal conductivity is achieved by changing the lattice symmetry and modulating the elastic modulus from 56.3 to 89.7 GPa owing to the ferro-elastic to para-elastic transition. In this study, we demonstrated that Mn2V2O7 crystals can serve as simple triggers (temperature stimuli) with adjustable switching temperature (290–350 K) and hysteresis temperature (18–31 K) by doping engineering with a thermal conductivity on/off ratio ranging from 1.17 to 1.49.