ANOMALY IN THE WIEDEMANN-FRANZ LAW CAUSED BY CHARGE CARRIERS ELECTRON-HOLE CONVERSION

The aim was to determine which of quasiparticles − the electrons (e) or the hols (h) − is more effective in the diffuse thermal conductivity channel of the high-entropy Al0.5CoCuCrNiFe alloy. The analysis was based on the temperature dependences of the absolute thermoelectric power S(T), electrical resistance R(T), and the scaled thermal conductivity χ*(T), the latter of which reflects qualitatively the temperature behavior of the real thermal conductivity χ(T). It was found that these dependences exhibit specific features in the range of ~250…140 K, with the resistive anomaly sign being “+” and the thermoelectric and thermophysical anomalies signs being “–”. Based on the fact that the Al0.5CoCuCrNiFe is an electron-hole conductor, arguments are presented that the S-anomaly reflects the presence of a crossover of latent hole↔electron conversions, resulting in an increase in the concentration Ch of holes charge carriers. Combined with the sign “–” of the thermophysical anomaly, this answers the question posed: in the diffuse heat transfer channel of the Al0.5CoCuCrNiFe, holes are less efficient than electrons. The reason for this is revealed by the sign “+” of the resistive anomaly, indicating the ratio of electron and hole mobilities ue>uh. The theory also posits that the specific electron component of thermal conductivity is greater than the corresponding holes component.