  Taking advantage of phase-transition and reconfigurable metamaterials,
dynamic control of nanoscale thermal modulation can be achieved through the
near-field radiative thermal rectification devices. In this work, an
active-tuning near-field thermal rectifier using reconfigurable
phase-transition metamaterials is explored. The rectifier has two terminals
separated by vacuum, working under a controllable operational temperature
around the critical temperature of the phase-transition material VO2. One of
the terminals is a stretchable structure made of PDMS thin film and grating
consisting of various types of phase-transition material. The effects of
various inclusion forms and all the related geometric parameters are well
analyzed. The controllable nanoscale thermal modulation can be achieved and the
ultrahigh rectification ratios of 23.7 and 19.8, the highest values ever
predicted, can be obtained for two deformation scenarios, respectively. It will
shed light on the dynamic tuning of small-scale thermal transport and light
manipulation.
