Strain controlled thermal regulator realized in two-dimensional black and blue phosphorene in-plane heterostructure

The reversible phase transition of two-dimensional material allotropes induced by strain engineering has promising applications in nanoelectromechanical systems and memories. Here, we report a series of black and blue phosphorene superlattice (BBPS) can be formed by reversible phase transition between them. The phase transition is with low-energy barrier and can be well regulated by strain engineering, until black phosphorene phase is fully transformed into blue phosphorene phase under strain of {ε} = 23%. At room temperature, BBPS exhibits a high phase transition rate of about 10⁶ Hz, which enables reversible phase transition rapidly. Beyond, the unique in-plane heterostructure of BBPS suppresses phonon transmission, lowering thermal conductivity to only 25.6% of black phosphorene. Beyond, nonequilibrium Green's function calculations indicate the thermal conductivity crossing the black-blue phosphorene heterojunction suddenly drops to only 1/3 that of black phosphorene. Therefore, strain engineering can not only achieve reversible phase transition but also modulate the thermal conductivity in very large range, which is excellent in the field of heat flow manipulation and thermal management.