ダイラックプラズマの巨大磁阻力
Na Xin1,2, James Lourembam1, Piranavan Kumaravadivel1,2
1Department of Physics and Astronomy, University of Manchester, Manchester, UK.
Nature
|April 12, 2023
まとめ
グラフェン
科学分野:
- 凝縮物質物理学
- 材料科学
- 量子力学
背景:
- グラフェンの電子スペクトルは ダイラック点という 異常な量子現象の領域を特徴としています
- 高温では,ディラックフェルミオンは電子穴プラズマを形成し,量子批判的分散と水力動的流れを示します.
- このディラックプラズマの磁場での行動は ほとんど未知のままです
研究 の 目的:
- ダイラック・プラズマの磁気伝達特性について 量子批判的な状態で調査する
- 室温と磁場における単層グラフェンの独特の磁力抵抗現象を特徴づける.
主な方法:
- 単層グラフェンの磁気輸送を様々な温度と磁場で実験的に測定する.
- パラボリックおよび線形体制に焦点を当てた磁気抵抗性の分析.
- 量子批判的システムとウェイル金属の理論的予測との比較.
主要な成果:
- 室温で低磁場 (0.1T) で観測された巨大なパラボリック磁気抵抗性 (>100%) は,他の材料よりも数桁高い.
- この効果は単層グラフェンに特有のもので,その質量のないスペクトルと高い可動性があることが実証された.
- プラズマが0番目のランドーレベルにあるとき,より高いフィールド (数テスラ) で巨大な線形磁力抵抗性を報告し,温度独立と多体起源を示している.
結論:
- 単層グラフェンのディラックプラズマは 磁場における前例のない磁気抵抗効果を示しています
- これらの発見は奇妙な金属とウェイル半金属との類似性を強調し,量子的重要な現象を研究するためのプラットフォームを提供します.
- 独特の磁気輸送特性により,グラフェンの高度な電子アプリケーションの可能性を強調しています.
関連する概念動画
01:24Potential Due to a Magnetized Object
324
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
The vector...
324
01:30Paramagnetism
2.6K
Paramagnets are materials with unpaired electrons that possess a finite magnetic moment. In the absence of a magnetic field, these moments are randomly oriented, and thus the net moment is zero. Under an external field, a torque acting on the moments tends to align them along the field's direction. However, the random thermal motion of electrons produces a torque opposite to the external field and tries to disorient the moments. These two competing effects align only a few moments along the...
2.6K
01:23Magnetic Field due to Moving Charges
8.9K
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
8.9K
01:31Magnetic Susceptibility and Permeability
1.2K
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
1.2K
01:26Diamagnetism
2.5K
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
2.5K
01:15Magnetic Vector Potential
714
In electrostatics, the electric field can be written as the negative gradient of the potential. In magnetostatics, the zero divergence of the magnetic field ensures that the magnetic field can be expressed as the curl of a vector potential. This potential is known as the magnetic vector potential.
Consider an ideal solenoid with n turns per unit length and radius R. If I is the current through the solenoid, the magnetic field inside the solenoid is expressed as the product of vacuum...
Consider an ideal solenoid with n turns per unit length and radius R. If I is the current through the solenoid, the magnetic field inside the solenoid is expressed as the product of vacuum...
714