室温のシリコンにおけるスピン偏振の電気的生成
Saroj P Dash1, Sandeep Sharma, Ram S Patel
1MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
Nature
|November 27, 2009
まとめ
この研究は,n型およびp型シリコンの両方で室温の電気スピン注入および検出を実証しています. このブレークスルーにより,環境温度でのシリコンスピントロニクスにより,高度なナノ電子機器の製造が可能になります.
科学分野:
- 半導体物理学 半導体物理学
- スピントロニクス (Spintronics) は,スピントロニクス (Spintronics) を開発したものです.
- マテリアルサイエンス 材料科学
背景:
- Spintronicsは電子のスピンをデジタル情報のために利用し,潜在的にナノエレクトロニクスに革命をもたらします.
- 半導体における現在のスピン操作は,低温 (<150 K) とn型材料に限られている.
研究 の 目的:
- 室温の電気スピンインジェクションとシリコンの検出を実証するために.
- 環境温度でのn型およびp型シリコンの両方のスピントロニック機能を可能にするために.
主な方法:
- 鉄磁気トンネルからシリコンへの電気スピン注入.
- ハンレ効果によるスピン操作.
- 誘導されたスピン蓄積の電気検出.
主要な成果:
- n型およびp型シリコンで室温スピンインジェクションを達成しました.
- n型シリコン (4.6%の極化) で2.9meVまでのスピン分裂が実証されている.
- 抽出されたスピン寿命 >140 ps (電子) と >270 ps (穴) で 300 K.
- spin 拡散の長さは230 nm (電子) と310 nm (穴) よりも大きい.
結論:
- この研究は,室温で動作するシリコンスピントロニックデバイスへの道を開く.
- 補完的なシリコンデバイスと回路におけるスピン機能の探索を可能にします.
- 環境条件下でのシリコンのスピンの基本的な振る舞いについての洞察を提供します.
関連する概念動画
Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
Atomic Nuclei: Nuclear Spin State Population Distribution
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
Types of Semiconductors
Intrinsic semiconductors are highly pure materials with no impurities. At absolute zero, these semiconductors behave as perfect insulators because all the valence electrons are bound, and the conduction band is empty, disallowing electrical conduction. The Fermi level is a concept used to describe the probability of occupancy of energy levels by electrons at thermal equilibrium. In intrinsic semiconductors, the Fermi level is positioned at the midpoint of the energy gap at absolute zero. When...
Spin–Spin Coupling Constant: Overview
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Induced Electric Dipoles
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Dielectric Polarization in a Capacitor
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...


