Exploring finite-temperature electronic transport in CoSi alloys with transition metals (Cr, Mn, Fe, and Ni) using the KKR-CPA method

The finite-temperature electronic transport properties of the CoSi compound and its alloys with 3d transition metals including Fe, Cr, Mn, and Ni are elucidated by using the Korringa-Kohn-Rostoker Green's function method combined with the coherent potential approximation. On the basis of the linear response theory, the electrical resistivity of the CoSi compound observed in the experiments could be quantitatively reproduced by taking into account both local phonon displacements and antisite disorder effects. Our calculations reveal the formation of Co-Si disorders with a very small concentration and their dominant effect on resistivity in a low-temperature range. Moreover, alloying transition metals with CoSi also led to significant changes in the states of conduction electrons, which is interesting as a typical example of a rigid band scheme. Notably, we found that alloying with Ni could reduce the system's resistivity by more than 25%, suggesting its potential for enhancing the power factor of the CoSi compound for thermoelectric applications. An effective combination of the KKR-CPA method and the Kubo-Greenwood formula allows quantitative reproduction of electrical resistivity of CoSi and its alloys with 3d transition metals.