耦合双量子点的磁序与电子结构

The magnetic order and electronic structure in a coupled double quantum-dot

耦合双量子点中电子间静电相互作用对电子在系统中隧穿效应具有重要影响.考虑电子隧穿,交换及Hubbard关联作用后,在单态近似下,本文求解了耦合双量子点二电子问题,讨论了铁磁基态及Mott局域化态出现的条件.这里的结果表明电子的隧穿不利于铁磁基态的形成,Hubbard关联越强越有利于Mott局域化态的形成,并且在交换作用下Mott局域化态会转变为铁磁基态.此外,外场可以诱导磁序相的改变.

Single-electron tunneling through two coupled quantum dots is strongly influenced by the electrostatic interaction between the dots. In this paper,a model of coupled double quantum-dot is investigated in the single state approximation. The model is solved exactly. The electron tunneling,exchange and Hubbard correlation effects are discussed. It is found that electron hopping weakens the ferromagnetic order; the Hubbard correlation strengthens the formation of Mott localization state. Furthermore, the Mott localization state has to transfer to the ferromagnetic state with the exchange interaction existing. In addition,the magnetic order may be changed when a sufficient strong magnetic field is imposed.