  We prove analytically the ballistic thermal rectification effect (BTRE) in
the Corbino disk characterized by an annular shape. We derive the thermal
rectification efficiency (RE) and show that it can be expressed as the product
of two independent functions, the first dependent on the temperatures of the
heat baths and the second on the system's geometry. It follows that a perfect
BTRE can be reached with the increase of the ratios of the heat baths'
temperatures and of the radius of the outer edge to the inner edge of the disk.
We also show that, by introducing a potential barrier into the Corbino disk,
the RE can be greatly improved. Quite remarkably, by an appropriate choice of
parameters, the thermal diode effect can be reversed. Our results are robust
under variation of the Corbino geometry, which may provide a novel and flexible
route to manipulate the heat flow at the nanoscale.
