Constantan is a good metal-alloy thermoelectric material. It has been used in thermocouples because of its good mechanical properties, wide applicable temperature range, large thermopower and low cost. Formation of resonant levels due to Ni 3d levels is known as the cause of large Seebeck coefficient. By adding doping atoms with large Pauling electronegativity, such as bromine in this case, it is found that one can improve the efficiency of the resonance, much as described by the theory of Mahan and Sofo1and our own work on semiconductors2. As a result, an increase in Seebeck coefficient and resistivity is seen, leading to an enhancement in thermopower from room temperature to 900K. The new alloy can have potential applications in various thermoelectric devices where the mechanical strength of metals confer them an advantage over semiconductors. Work supported by the AFOSR MURI “Cryogenic Peltier Cooling”, FA9550-10-1-0533.
1. G. D. Mahan and J. O. Sofo, Proc. Natl. Acad. Sci. U. S. A.,93, 7436 (1996).
2. Joseph P. Heremans, Bartlomiej Wiendlocha and Audrey M. Chamoire,Energy Environ. Sci., 5, 5510-5530 (2012).