  In this work, we study the near-field radiative heat transfer between two
suspended sheets of anisotropic 2D materials. It is found that the radiative
heat transfer can be enhanced with orders-of-magnitude over the blackbody limit
for nanoscale separation. The enhancement is attributed to the excitation of
anisotropic and hyperbolic plasmonic modes. Meanwhile, a large thermal
modulation effect, depending on the twisted angle of principal axes between the
upper and bottom sheets of anisotropic 2D materials, is revealed. The
near-field radiative heat transfer for different concentrations of electron is
demonstrated and the role of hyperbolic plasmonic modes is analyzed. Our
finding of radiative heat transfer between anisotropic 2D materials may find
promising applications in thermal nano-devices, such as non-contact thermal
modulators, thermal lithography, thermos-photovoltaics, etc.
