When heat transfers through interface between two different materials, it will encounter an interfacial thermal resistance (ITR) that makes the temperature discontinuous. This effect has been totally neglected so far in the research of thermal cloak, in particular when the thermal cloak is built with multilayer structures. In this paper, we investigate the effect of ITR on the performance of the thermal cloak by using both analytical and numerical method. Our results show that the existence of ITR will distort the external field, thus destroy the cloak. Moreover, we found that the effect of ITR can be quantified by a parameter called characteristic length.

7 pages, 7 figures