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稀磁半导体具有能同时调控电荷与自旋的特性,是破解摩尔定律难题的候选材料之一.我们团队率先提出了稀磁半导体中自旋和电荷掺杂分离的机制,探索并研制了新一代稀磁半导体材料,为突破经典稀磁半导体材料的制备瓶颈提供了有效解决方案.以(Ba,K)(Zn,Mn)2As2等为代表的新一代稀磁半导体,通过等价态的Mn掺杂引入自旋、异价态的非磁性离子掺杂引入电荷,成功实现了230 K的居里温度,刷新了可控型稀磁半导体的居里温度记录.本文将重点介绍几种代表性的新一代稀磁半导体的设计与研制、新一代稀磁半导体的综合物性表征、大尺寸单晶生长以及基于单晶的安德烈夫异质结研制.我们团队通过新一代稀磁半导体的新材料设计研制、综合物性研究、简单原型器件构建的“全链条”模式研究,开拓了自旋电荷分别掺杂的稀磁半导体材料研究领域,充分展现了自旋和电荷掺杂分离的新一代稀磁半导体材料潜在应用前景. 相似文献
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稀磁半导体--自旋和电荷的桥梁 总被引:5,自引:0,他引:5
稀磁半导体可能同时利用载流子的自旋和电荷自由度构造将磁、电集于一体的半导体器件.尤其是铁磁半导体材料的出现带动了半导体自旋电子学的发展.室温铁磁半导体材料的制备,半导体材料中有效的自旋注入,以及自旋在半导体结构中输运和操作已成为目前半导体自旋电子学领域中的热门课题.稀磁半导体呈现出强烈的自旋相关的光学性质和输运性质,这些效应为人们制备半导体自旋电子学器件提供了物理基础. 相似文献
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稀磁半导体Zn1—xCoxSe的光谱特性 总被引:2,自引:0,他引:2
本文首次报道一类新型半导体材料:含Co^+6+离子的稀磁半导体Zn1-xCoxSe晶体的光谱特性研究实验结果。对组分x=0.001,0.0097,0.030,0.037系列样品,在73K-300K范围内分别在可见和近红外区测量了吸收光谱和光致发光谱。实验观测到一系列与x值无关的吸收峰和光致发光峰,两者一一对应,它们分别对应于具有Td对称的晶体场中Co^+^+离子不同能级间的跃迁,对这些峰进行了初步 相似文献
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基于单电子有效质量近似理论和传递矩阵方法,理论研究了稀磁半导体/半导体超晶格结构中电子的自旋极化输运特性.主要讨论了光场和磁场联合调制对自旋极化输运的影响,以及不同自旋电子在该超晶格结构中的隧穿时间.理论和数值计算结果表明,由于导带电子与掺杂Mn离子之间的sp-d电子相互作用引起巨塞曼劈裂,因此在磁场调制下,不同自旋电子在该结构中感受到的势函数不同而呈现出自旋过滤效应,不同自旋电子的共振透射能带的位置和宽度可以通过磁场进行调制.同时在该结构中考虑光场时,自旋依赖的透射谱会因为吸收和发射光子而呈现出对光场的强度和频率响应;最后,通过不同自旋电子的高斯波包在该结构中随时间的演化给出了不同自旋电子的隧穿时间.本文研究结果对研究和设计基于稀磁半导体/半导体超晶格结构的高速量子器件具有一定的指导意义. 相似文献
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First-Principles Studies for the Electronic Structures of Diluted Magnetic Semiconductors (Ga, Fe)As
First-principles LMTO-ASA band calculations are performed for Ga1-xFexAs (x = 1, 1/4, 1/8) by assuming supercell structures. It is found that the antiferromagnetic (AFM) state is stable for x = 1/4. For x = 1/8, ferromagnetic(FM) state is more stable than AFM state, and no stable magnetic state exists for x = 1. In both the cases the magneticmoments of As and Ga atoms are parallel to those of the nearest Fe atoms due to the p-d hybridization. Further, theband structure shows rather localized Fe 3d state in the gap, and the parallel polarization is confined rather in thevicinity of Fe site. 相似文献
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First-Principles Studies for the Electronic Structures of Diluted Magnetic Semiconductors (Ga, Fe)As
WEIShu-Yi WANGTian-Xing YANGZong-Xian MALi 《理论物理通讯》2003,40(4):499-502
First-principles LMTO-ASA band calculations are performed for Ga1-xFezAs (x = 1, 1/4, 1/8) by assuming supercell structures. It is found that the antiferromagnetic (AFM) state is stable for x = 1/4. For x = 1/8, ferromagnetic (FM) state is more stable than AFM state, and no stable magnetic state exists for x = 1. In both the cases the magnetic moments of As and Ga atoms are parallel to those of the nearest Fe atoms due to the p-d hybridization. Fhrther, the band structure shows rather localized Fe 3d state in the gap, and the parallel polarization is confined rather in the vicinity of Fe site. 相似文献
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Electron spin resonance investigation of the substitution of Fe3^+ for Ti4^+ ions in rutile TiO2 single crystal 下载免费PDF全文
A Fe doped rutile TiO 2 single crystal is grown in an O 2 atmosphere by the floating zone technique.Electron spin resonance (ESR) spectra clearly demonstrate that Fe 3+ ions are substituted for the Ti 4+ ions in the rutile TiO 2 matrix.Magnetization measurements reveal that the Fe:TiO 2 crystal shows paramagnetic behaviour in a temperature range from 5 K to 350 K.The Fe 3+ ions possess weak magnetic anisotropy with an easy axis along the c axis.The annealed Fe:TiO 2 crystal shows spin-glass-like behaviours due to the aggregation of the ferromagnetic clusters. 相似文献
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A series of Mn-doped ZnO films have been prepared in different sputtering plasmas by using the inductively coupled plasma enhanced physical vapour deposition. The films show paramagnetic behaviour when they are deposited in an argon plasma. The Hall measurement indicates that ferromagnetism cannot be realized by increasing the electron concentration. However, the room-temperature ferromagnetism is obtained when the films are deposited in a mixed argon-nitrogen plasma. The first-principles calculations reveal that antiferromagnetic ordering is favoured in the case of the substitution of Mn^2+ for Zn^2+ without additional acceptor doping. The substitution of N for O (NO^-) is necessary to induce ferromagnetic couplings in the Zn-Mn-O system. The hybridization between N 2p and Mn 3d provides an empty orbit around the Fermi level. The hopping of Mn 3d electrons through the empty orbit can induce the ferromagnetic coupling. The ferromagnetism in the N-doped Zn-Mn-O system possibly originates from the charge transfer between Mn^2+ and Mn^3+ via NO^-, The key factor is the empty orbit provided by substituting N for O, rather than the conductivity type or the carrier concentration. 相似文献
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G. Schmidt R. Fiederling M. Keim G. Reuscher T. Gruber W. Ossau A. Waag L. W. Molenkamp 《Superlattices and Microstructures》2000,27(5-6)
Spin injection into semiconductors has been a field of growing interest during recent years, because of the large possibilities in basic physics and for device applications that a controlled manipulation of the electrons spin would enable. However, it has proven very difficult to realize such a spin injector experimentally. Here we demonstrate electrical spin injection and detection in a GaAs/AlGaAs p-i-n diode using a semimagnetic II–VI semiconductor (Zn1 − x − yBexMnySe) as a spin aligner. The degree of circular polarization of the electroluminescence from the diode is related to the spin polarization of the conduction electrons. Thus, it may be used as a detector for injected spin-polarized carriers. Our experimental results indicate a spin polarization of the injected electrons of up to 90% and are reproduced for several samples. The degree of optical polarization depends strongly on the Mn concentration and the thickness of the spin aligner. Electroluminescence from a reference sample without spin aligner as well as photoluminescence after unpolarized excitation in the spin aligner sample show only the intrinsic polarization in an external magnetic field due to the GaAs bandstructure. We can thus exclude side effects from Faraday effect or magnetic circular dichroism in the semimagnetic layer as the origin of the observed circularly polarized electroluminescence. 相似文献
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利用水热法制备了Zn1-xFexO(x=0,0.01,0.05,0.10和0.20)纳米稀磁半导体材料。由X射线衍射图谱的结果表明,制备的Zn1-xFexO样品为纤锌矿结构,没有金属铁等第二相出现;高分辨透射电子显微镜的结果表明,形貌为分散性良好的纳米颗粒,晶格清晰;拉曼光谱结果表明(E2High)峰位向高频移动,半高宽宽化,峰强减弱;光致发光光谱结果表明,随着Fe离子的掺入,紫外峰向低能移动,光致发光光谱发生了猝灭现象;UV-Vis光谱可看出,光学带隙减小,发生了红移现象。这些结果表明Fe3+成功替代Zn2+进入到ZnO晶格。 相似文献
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不同的制备工艺对ZnO薄膜的微结构和性能有很大的影响,为了得到成本较低,样品具有较好特性的实验方法,对于制备手段进行了探索。使用PVA溶胶-凝胶法制备了Zn0.88Co0.12O薄膜,研究了不同退火工艺对其微结构的影响。对于Zn0.88Co0.12O样品的微结构和室温下的铁磁性和发光特性,具体比较分析了产生原因。对比了Co掺杂和复合Co、Fe掺杂Zn0.88(Co0.5Fe0.5)0.12O样品的微结构,采用振动样品磁强计(VSM)测量了样品的磁特性,发现单一掺杂的薄膜具有更好的晶体质量和更强的磁性。 相似文献