界面量子起伏对铁电超晶格介电性质的影响

应用平均场理论，在横场伊辛模型的框架内，研究了界面量子起伏对铁电超晶格介电性质的影响。得到界面的量子起伏会导致铁电超晶格的介电极化率的升高。     

超晶格微制冷器物理模型分析

对InGaAsP/InGaAs组成的超晶格,基底为InP的固体微制冷器进行了初步研究,发现热电和热电子转换同时存在于超晶格微制冷器中。提出了简化后的物理模型,具体分析了影响热电转换效率的热阻和电阻、制冷影响因素和误差等因素,计算结果与实际器件接近。     

POSITIVE MAGNETORESISTANCE IN NI/W SUPERLATTICES

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｍａｇｎｅｔｉｃａｎｄｔｒａｎｓｐｏｒｔｐｒｏｐｅｒｔｉｅｓｏｆｔｈｉｎｍａｇｎｅｔｉｃｍｕｌｔｉｌａｙｅｒｓｈａｖｅａｔｔｒａｃｔｅｄｃｏｎｓｉｄｅｒａｂｌｅａｔｔｅｎｔｉｏｎｄｕｒｉｎｇｔｈｅｐａｓｔｙｅａｒｓ.Ｓｉｎｃｅｄｉｓｃｏｖｅｒｙｏｆｎｅｇａｔｉｖｅｇｉａｎｔｍａｇｎｅｔｏｒｅｓｉｓｔａｎｃｅ (ＧＭＲ)ｂｙＢａｉｂｉｃｈｅｔａｌ.ｉｎＦｅ/Ｃｒｍｕｌｔｉｌａｙｅｒｓ (Ｂａｉｂｉｃｈ ,1 998) ,ｅｘｔｅｎｓｉｖｅｒｅｓｅａｒｃｈｈａｓｂｅｅｎｄｏｎｅｃｏｎ ｃ…     

共轭梯度法研究超晶格GaAs/AlxGa1－xAs的电子结构

改进了一种从头计算方法—共轭梯度方法 ,研究了超晶格 Ga As/ A lx Ga1 - x A s的电子结构 .根据超晶格的基本方程 ,在固定电子密度 n(z)下 ,求解了基本方程的本征值和本征函数 ,并由它们组成新的 n(z) ,重复此过程直到得自洽解 .另按超晶格基本方程的具体情况 ,对每个 kz独立地应用了共轭梯度方法 ,此可大大节省与 Gram-Schm it正交化有关的时间 .计算了超晶格的两个最低子能带之间的能量差和 F ermi能量 ,其模拟计算的结果与对应的实验数值一致     

磁场作用下超晶格单量子阱中束缚态的能级

超晶格由两种不同晶体材料交替生长的具有周期性结构的多层薄膜构成,两种材料的"势垒—势阱"结构就是量子阱.通过理想的无限深势阱模型,讨论了施加磁场作用的超晶格中单量子阱束缚态的能级结构和态密度,得到了体系的本征能量与本征函数.分析表明,沿超晶格生长方向能级不受外加磁场影响,垂直于超晶格生长方向以ωc为回旋频率的谐振运动,超晶格量子阱量子化能级高度简并,简并度和外加磁场成正比.     

MAGNETIC PROPERTIES OF TWO DIMENSIONAL ISING ANTIFERROMAGNET-ANTIFERROMAGNETIC SUPERLATTICE

An effective-field treatment for the two dimensional Isingantiferromagent-antiferromagnetic superlattice(AFAFS)without external field is pres-ented.The critical temperature dependence of the number of laycrs of superlattice cell andthe temperature dependence of magnetization of each layer in the superlattice are investi-gated.The similarity of the magnetic properties of AFAFS and those offerromagnet-ferromagnetic superlattice(FFS)is also discussed.     

分子束外延具有GaAs／AlGaAs超晶格缓冲层的量子阱材料

采用分子束外延技术（ＭＢＥ）生长了具有ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层的单量子阱和多量子阱材料．采用ＧａＡｓ／ＡｌＧａＡｓ超晶格缓冲层掩埋衬底缺陷，获得的量子阱结构材料被成功地用于制作量子阱激光器．波长为７７８ｎｍ的激光器，最低阈值电流为３０ｍＡ，室温下线性光功率大于２０ｍＷ．     

Valence band offsets of the strained and longitudinally relaxed diamond/c-BN superlattices

The valence band offsets of the strained and longitudinally relaxed diamond/cubic boron-nitride (c-BN) (110) superlattice are investigated by the plane wave density functional theory approach and using the on-site core electron as a reference energy level. For the strained diamond/c-BN superlattice, the valence band offset of around 1.50 eV is in good agreement with those using all the electrons methods. As for the longitudinally relaxed superlattice, the valence band offset of around 1.28 eV is smaller tha...     

半导体超晶格及其量子阱的原理

应用算符的方法及通过朗道能级的分析 ,得出了二维电子气的能级特性 ,由此通过态密度、简并度的讨论 ,研究了半导体超晶格量子阱的原理及其广泛的应用。     

Efficient interlayer charge release for high-performance layered thermoelectrics

Many layered superlattice materials intrinsically possess large Seebeck coefficient and low lattice thermal conductivity, but poor electrical conductivity because of the interlayer transport barrier for charges, which has become a stumbling block for achieving high thermoelectric performance. Herein, taking BiCuSeO superlattice as an example, it is demonstrated that efficient interlayer charge release can increase carrier concentration, thereby activating multiple Fermi pockets through Bi/Cu dual vacancies and Pb codoping. Experimental results reveal that the extrinsic charges, which are introduced by Pb and initially trapped in the charge-reservoir [Bi₂O₂]²⁺ sublayers, are effectively released into [Cu₂Se₂]²⁻ sublayers via the channels bridged by Bi/Cu dual vacancies. This efficient interlayer charge release endows dual-vacancy- and Pb-codoped BiCuSeO with increased carrier concentration and electrical conductivity. Moreover, with increasing carrier concentration, the Fermi level is pushed down, activating multiple converged valence bands, which helps to maintain a relatively high Seebeck coefficient and yield an enhanced power factor. As a result, a high ZT value of ∼1.4 is achieved at 823 K in codoped Bi_0.90Pb_0.06Cu_0.96SeO, which is superior to that of pristine BiCuSeO and solely doped samples. The present findings provide prospective insights into the exploration of high-performance thermoelectric materials and the underlying transport physics.