Specific heat studies in Ho�?�Ba�?�CuO superconductors: Fermionic and bosonic contributions

[摘要] The specific heats of superconducting HoBa₂Cu₃O_{7â€�?�ð�?��?} (ð‘�??_c â‰�?? 92 K) have been theoretically investigated in the temperature domain 70 â‰�? ð‘�?? â‰�? 110 K. The bosonic (phonons) contribution to the specific heat is estimated from Debye model in the harmonic approximation for high temperature expansion (ð‘�?? > 𝜃_D/2ðœ�?) using the moments of the phonon density of states. The fermionic constituent as the electronic specific heat is deduced using a suitable trial function above and below ð‘�??_c. As a next step the contribution of specific heat by charge oscillations (plasmons) are obtained. The theoretical results from bosonic and fermionic terms are then compared with the experimental results. We find that the specific heats from electronic as well as plasmon term are only a fraction of lattice specific heat and in particular, plasmons do not influence the thermal conduction significantly. The implications of the above analysis are discussed.

[学科分类] 材料工程

[关键词] Electronic;phonons;plasmons;specific heat;Ho-based superconductors.