  The discovery of an intrinsic antiferromagnetic topological insulator
(AFM-TI) in MnBi$_2$Te$_4$ has attracted intense attention, most of which lies
on its electrical properties. In this paper, we report electronic, thermal, and
thermoelectric transport studies of this newly found AFM-TI. The temperature
and magnetic field dependence of its resistivity, thermal conductivity, and
Seebeck coefficient indicate strong coupling between charge, lattice, and spin
degrees of freedom in this system. Furthermore, MnBi$_2$Te$_4$ exhibits a large
anomalous Nernst signal, which is associated with non-zero Berry curvature of
the field-induced canted antiferromagnetic state.
