摘要
Cobalt oxide,as one of the most fascinating examples of correlated electronic system,exhibits several exotic transport characteristics,such as superconductivity,charge ordering,and topological frustration.In this study,we are reporting the observation of another intriguing transport phenomenon in calcium cobaltates.Specifically,under a large magnetic field of 7 T,we observed an anomalously enhanced thermal conductivity that was accompanied with a largely suppressed thermopower.This observation reveals a hitherto undiscovered correlation between the two transport factors.Within the premise of Heisenberg model,we have shown that the observed experimental results can be explained consistently only if the magnon excitation is taken into account.Our study offers an insight into the puzzling origin of large thermopower observed in layered cobaltates and provides a specific strategy for further optimization of thermopower.
基金
the supports from National Natural Science Foundation of China through grant#52002383
Ningbo Municipal Bureau of Science and Technology through grant#202003N4365
supported by National Natural Science Foundation of China(Grant No.52001012)
Beijing Natural Science Foundation(Grant No.2214070).
