A heat pump that includes a thermoelectric device(s) and a heat sink having a raised portion with a top surface for thermally coupling with a planar face of the thermoelectric device(s). The raised portion of the heat sink includes an outer periphery and a raised central region surrounded by a void region to provide more uniform thermal conductivity when clamped within an assembly. The raised central region is shaped in an any shape corresponding to a shape of uneven thermal conductivity due to clamping pressure applied to the heat sink. The void region can be substantially contiguous and entirely circumscribe the central raised region. The device can optionally include discrete supports formed of a less thermally-conductive material within the void region. The supports can be elastomeric, such as O-rings, and disposed within pockets defined within the void region.