Fano effect of a parallel-coupled triple Rashba quantum dot system

Using the nonequilibrium Keldysh Green's function technique, the Fano effect of a parallel-coupled triple Rashba quantum dot system is investigated. The conductance as a function of electron energy is numerically calculated. Compared with the case of a parallel-coupled double quantum dot system, two additional Fano resonance peaks occur in the conductance spectrum. By adjusting the structural parameters, the two Fano resonance peaks may change into the resonance peaks. In addition, the influence of Rashba spin-orbit interaction on the conductance is studied.     

Thermopower in parallel double quantum dots with Rashba spin-orbit interaction

Based on the Green’s function technique and the equation of motion approach,this paper theoretically studies the thermoelectric effect in parallel coupled double quantum dots (DQDs),in which Rashba spin-orbit interaction is taken into account.Rashba spin-orbit interaction contributions,even in a magnetic field,are exhibited obviously in the double quantum dots system for the thermoelectric effect.The periodic oscillation of thermopower can be controlled by tunning the Rashba spin-orbit interaction induced phase.The interesting spin-dependent thermoelectric effects will arise which has important influence on thermoelectric properties of the studied system.     

物理参数对光限幅效应的影响

为了对抗日益严重的激光武器威胁，需要了解激光防护材料的光学性能。该文根据非线性吸收模型，推导出光限幅阈值表达式。并以表达式为理论依据，利用配位聚合物［Cd(L4)(SO4)(H2O)2］n在波长532nm、脉冲宽度为40ps的条件下所获得的实验数据，分析研究非线性吸收参数、线性透过率和有效激发态吸收截面等物理参数对光限幅效应的影响。以此为基础，研究了激光防护材料的非线性光学特性和光限幅特性，为制备光限幅材料提供了理论和实验依据。     

Thermospin effects in parallel coupled double quantum dots in the presence of the Rashba spinben orbit interaction and Zeeman splitting

The thermoelectric and the thermospin transport properties, including electrical conductivity, Seebeck coefficient, thermal conductivity, and thermoelectric figure of merit, of a parallel coupled double-quantum-dot Aharonov-Bohm interferometer are investigated by means of the Green function technique. The periodic Anderson model is used to describe the quantum dot system, the Rashba spin-orbit interaction and the Zeeman splitting under a magnetic field are considered. The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects. We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.     

Thermospin effects in parallel coupled double quantum dots in the presence of the Rashba spin-orbit interaction and Zeeman splitting

The thermoelectric and the thermospin transport properties,including electrical conductivity,Seebeck coefficient,thermal conductivity,and thermoelectric figure of merit,of a parallel coupled double-quantum-dot Aharonov-Bohm interferometer are investigated by means of the Green function technique.The periodic Anderson model is used to describe the quantum dot system,the Rashba spin-orbit interaction and the Zeeman splitting under a magnetic field are considered.The theoretical results show the constructive contribution of the Rashba effect and the influence of the magnetic field on the thermospin effects.We also show theoretically that material with a high figure of merit can be obtained by tuning the Zeeman splitting energy only.     

[(Ge5)Fe]∞/四元环二嵌段共聚小分子/[(Ge5)Fe]∞分子结自旋输运性质

采用密度泛函理论和非平衡格林函数相结合的计算方法,研究四元环二嵌段共聚小分子自旋输运性质以及嵌入嘧啶基对分子结输运性质的影响。研究发现中心区为4,4ˊ-二苯基联苯分子时,在极小偏压,磁阻接近于无穷大,随着偏压的增大磁阻逐渐减小,在较大偏压下磁阻变为负值。当嵌入嘧啶基后,在一定的偏压下,嵌入2个嘧啶基的分子结磁阻接近零,嵌入3个嘧啶基结构,磁阻小于零,嵌入4个嘧啶基结构时,磁阻最大。通过分析五种分子结在非平衡态下的透射谱,进一步对这些特性进行分析。     

Spin Accumulation in a Double Quantum Dot Aharonov-Bohm Interferometer

We investigate the spin accumulation in a double quantum dot Aharonov-Bohm （AB） interferometer in which both the Rashba spin-orbit （RSO） interaction and intradot Coulomb interaction are taken into account. Due to the existence of the RSO interaction, the electron, flowing through different arms of the AB ring, will acquire a spin-dependent phase factor in the tunnel-coupling strengths. This phase factor will induce various interesting interference phenomena. It is found that the electrons of the different spin directions can accumulate in the two dots by properly adjusting the bias and the intradot level with a fixed RSO interaction strength. Moreover, both the magnitude and direction of the spin accumulation in each dot can be conveniently controlled and tuned by the gate voltage acting on the dot or the bias on the lead.