Effects of La Substitution on the Energy Gaps and Superstructures of CeRhAs(Condensed Matter : Electronic Structure, Electrical, Magnetic and Optical Properties)

概要

論文の詳細を見る
Magnetic, transport and specific-heat measurements of Ce_<1-x>La_xRhAs (x≤0.1) have been performed. The host compound CeRhAs undergoes successive phase transitions with formation of superlattices at T_1=360, T_2=235, and T_3=165 K, respectively. The transitions at T_1 and T_3 are associated with the formation of a wide gap of E_<g1>/k_B=2200 K and a narrow one of E_<g2>/k_B=310 K, respectively. All anomalies at T_1, which are a jump in the specific heat C, a drop in the magnetic susceptibility χ and the activation-type behavior in the Hall coefficient, remain until x is increased up to 0.10, at which T_1 is depressed to 297 K. These observations indicate that both the phase transition at T_1 and the gap of E_<g1> remain up to x=0.10. Anomalies in C and χ at T_2 and T_3, on the other hand, vanish at a small concentration x=0.01. The semiconducting behavior in both the electrical resistivity and thermopower below T_3 also disappears at x=0.02. These facts corroborate that the narrow gap of E_<g2> is quenched when the phase transition at T_3 disappears. The distinct effects on the phase transitions in Ce_<1-x>La_xRhAs and CeRhAs_<1-y>Sb_y indicate that coherent hybridization between Rh 4d and As 4p states is important for the formation of E_<g1> below T_1.
社団法人日本物理学会の論文
2005-12-15