鉄電気表面に電子トンネルを掘り込むポラライゼーション制御
Peter Maksymovych1, Stephen Jesse, Pu Yu
1Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. maksymovychp@ornl.gov
Science (New York, N.Y.)
|June 13, 2009
まとめ
研究者は,自発的偏振を用いて,鉄電性物質の電子輸送を制御した. この鉄電スイッチングはトンネリング電流を500倍増幅し,潜在的なデータストレージとスピントロニクスアプリケーションを可能にしました.
科学分野:
- マテリアルサイエンス 材料科学
- 凝縮物質物理学 凝縮物質物理学
- ナノテクノロジー ナノテクノロジー
背景:
- 鉄電気材料は自発的な電極化を示し,外部の電場によって切り替えることができます.
- ナノスケールでの電子輸送の制御は,高度な電子機器の開発に不可欠です.
- 鉛ジルコネートチタナート (Pb(Zr0.2Ti0.8) O3またはPZT) は,顕著な自発的偏化を持つ有名な鉄電ペロブスキートです.
研究 の 目的:
- 鉄電酸化物フィルム内の局所電子伝送の再現可能な制御を実証するために.
- 電子トンネリング電流の電鉄電極化スイッチングの影響を調査するために.
- データストレージとスピントロニクスにおける潜在的な応用を探求する.
主な方法:
- 原子力顕微鏡 (AFM) を使用して,電子を薄いPZTフィルムに注入します.
- フォウラー・ノルドハイムトンネル方式で,高い電場下で運行しています.
- トンネリング電流のヒステレスと,その相関関係と鉄電スイッチングの測定と分析.
主要な成果:
- 自発的偏極化による局所電子輸送の高度な再現制御を達成した.
- トンネリング電流における顕著なヒステリーシスを観測し,鉄電極化スイッチングと同期した突然のスイッチングイベントを観測した.
- 鉄電スイッチングによるトンネリング電流の最大500倍の増幅が実証されています.
- この効果の静電制御をフェロ電気スイッチングで示した.
結論:
- 鉄電気PZTフィルムのローカル電子輸送は,自発的偏振を操作することによって効果的に制御することができます.
- 鉄電スイッチングは,電子トンネル電流を大幅に増幅し,新しい電子機能のための有望なメカニズムを提供します.
- 実証された制御と増幅は,超高密度データストレージと高度なスピントロニックデバイスの可能性を示唆しています.
関連する概念動画
01:29Potential Due to a Polarized Object
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
01:31Dielectric 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...
01:27Biasing of Metal-Semiconductor Junctions
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
01:22Biasing of FET
Biasing a Junction Field Effect Transistor (JFET) is crucial for setting operational parameters and ensuring efficient functioning in electronic circuits. JFETs are characterized by using a single carrier type in N-channel or P-channel configurations, where the channel is surrounded by PN junctions. These junctions are central to the device's ability to control current flow.
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
01:28Induced 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...
01:24Metal-Semiconductor Junctions
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...