自旋電子學(xué)ppt課件-資料下載頁(yè)
2025-05-04 12:06本頁(yè)面
【正文】 何為自旋電子學(xué)？ 現(xiàn)代信息技術(shù) ： 信息處理 和 信息存儲(chǔ) ＝自旋電子學(xué) 半導(dǎo)體材料 磁性材料 電子電荷 電子自旋 ＋ ? 傳統(tǒng)電子學(xué) : 使用電子電荷特征來(lái)操控器件以獲得不同功能 – 例如 , 二極管 , 晶體管 , 光電器件 (探測(cè)器和激光器 ….) ? 自旋電子學(xué) : 使用電子自旋來(lái)獲得新的或優(yōu)化的功能器件 自旋晶體管 內(nèi)存 (高速，低功耗 ), 可調(diào)的探測(cè)器和激光器 , 量子計(jì)算機(jī)等 …. Polarization up Polarization down No information Information = 1 Information = 0 Spin direction random Polarization =0 自旋量子計(jì)算機(jī) SpinLED 有了 GMR，還需要 DMS嗎？ DMS與 GMR之比較 InterestWhy Magic Semiconductors? Field of Spintronics: Essential to develop a semiconductor free from cluster amp。 secondary phase Having ferromagically polarized carriers at Troom Spin amp。 Charge of the carriers can be coupled with an external field Control devices Electron charge Spintronics Spin The ideal material retains the properties of the “host” semiconductor amp。 adds FM at Troom DMS O Zn TM What is the structure of DMS? 其實(shí)在 1990s人們關(guān)注的 InAs， GaAs等 Ⅲ － Ⅵ 稀磁半導(dǎo)體， 但其距離溫度小于 172 K。 為什么人們關(guān)注 ZnO稀磁半導(dǎo)體的研究？ 稀磁半導(dǎo)體 So far, several models have been proposed to explain the mechanism of magic origin in DMS. Competing Magic Mechanisms (1) Thermally activated hopping seen at high temperatures and in relatively pure samples: (2) Varible range hopping seen at low temperature in impure samples α =1/4 or 1/2 (3) Metallic (need mean free path greater than lattice spacing) Three possible types of conductivity 2?? EAe ?? kT1???? ???????? TTBe 0Fknemne???? 22 ???a???Antiferro Isolated ion Isolated polaron pair Overlapping polarons High resistance regime The donors defects tend to form bound magic polarons, coupling the 3d moments of the ions within their orbits. Provided the orbit is large enough, overlap between a hydrogenic electron and the cations within its orbit leads to ferromagic exchange coupling between them As the density of defects increases, the hydrogenic orbitals associated with the randomly distributed defects overlap. At the percolation threshhold, ferromagism sets in. (ZnCo)O Electrons Holes Impurity band n(E) E Again, TM supplies the magic moments and the carriers Donor level nType Ferromagism 作業(yè) ?論述 GMR和 TMR的應(yīng)用以及對(duì)信息存儲(chǔ)產(chǎn)業(yè)帶來(lái)的影響。 謝 謝！ Thank you for your attention
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