Origin of Semi-Metallic Behaviour in the Charge-Ordered State of Yb₄As₃

抄録

Yb₄As₃ has been known as a heavy fermion compound with very low carriers.Recently, polarised neutron measurement has revealed the charge-ordered statein the low temperature phase after a structural phase transition.To clarify the conducting property, a band structure is calculated for hypothetical LuYb₃As₃ where Yb³⁺ are replaced with Lu, as it is a nonmagnetic reference material of the charge-ordered state ofYb³⁺Yb₃²⁺As₃^3-.The result shows LuYb₃As₃ to be a semi-metal with As-4p holes andLu-5d electrons, which is consistent with the semi-conducting behaviour of thecharge-ordered state.The Fermi surfaces are located on a plane normal to the Yb³⁺ chainwith q = 0.