来自多重费米子的奇拉异常的内在负磁电阻
Federico Balduini1, Alan Molinari2, Lorenzo Rocchino2
1IBM Research Europe - Zurich, Säumerstrasse, Ruschlikon, Switzerland. ico@zurich.ibm.com.
Nature communications
|August 2, 2024
概括
奇拉异常,粒子运动的不平衡,在CoSi.内的多重费米子中得到证实. 这一发现扩大了对这种现象的理解,超越了韦尔费米子,到固态材料中的高自旋准粒子.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 量子材料是一种量子材料.
- 固态物理 固态物理
背景情况:
- 奇拉异常是韦尔费米子的一个关键特征,解释了负纵向磁阻等现象.
- 多重叠费米子是在奇拉晶体中发现的韦尔准粒子的高自旋概括.
- 除了韦尔费米子之外的奇拉异常的普遍性仍然是一个开放的问题.
研究的目的:
- 为了研究多重费米子中的奇拉异常.
- 为了确定奇拉异常是否是一种适用于高自旋准粒子的一般现象.
- 确定适合用于研究内在性异常的材料.
主要方法:
- 实验测量了CoSi中的磁传输.
- 使用挤压测试来排除外部影响,如电流喷射.
- 开发一个半古典理论来解释观察到的磁阻.
主要成果:
- 在CoSi中观察到内在的纵向负磁电阻,这归因于多倍费米子的奇拉异常.
- 在费米水平周围的显著能量窗口 (~0.85 eV) 中确认了多重带.
- 证明负磁阻源于性异常,即使有轨磁矩贡献.
- 观察到一种非线性霍尔效应,支持多重叠费米子起源.
结论:
- 对于韦尔费米子 (多重费米子) 的更高自旋概括来说,性异常得到证实.
- CoSi 作为一个平台来研究固态系统中的内在性异常.
- 这项研究扩大了奇拉异常的范围,超出了传统的韦尔子.
相关概念视频
Diamagnetism
2.4K
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....
2.4K
Paramagnetism
2.5K
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...
2.5K
Ferromagnetism
2.4K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K
Magnetic Susceptibility and Permeability
1.0K
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...
1.0K
Potential Due to a Magnetized Object
270
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...
270
Atomic Nuclei: Nuclear Magnetic Moment
1.1K
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...
1.1K


