超导性和量子化异常的霍尔效应
Youngjoon Choi1, Ysun Choi1, Marco Valentini1
1Department of Physics, University of California at Santa Barbara, Santa Barbara, CA, USA.
Nature
|March 5, 2025
概括
研究人员使用堆叠的石墨烯层创造了一种新材料, 在零磁场下表现出量子异常的霍尔和超导状态. 这一突破使得可调节的拓边缘模式可以用于可重新配置的量子设备,
科学领域:
- 凝聚物质物理学
- 材料科学
- 量子物理学
背景情况:
- 预计在奇拉边缘状态中的超导相关性会产生拓保护的零能量模式.
- 现有的实验方法往往存在界面障碍,阻碍了孤立的拓模式的形成.
- 低密度平带材料为通过电场调整超导和量子异常哈尔状态提供了一个有希望的替代方案.
研究的目的:
- 在一个低混乱的系统中实现同时量子化传输和超导.
- 探索工程石墨烯异构结构对拓量子现象的潜力.
- 调查拓边缘状态的调整性和重新配置性.
主要方法:
- 用六角化物对齐的四层石墨烯的制造.
- 使用电场效应调整材料状态.
- 使用热力学压缩性测量.
- 整合过渡金属二甲基层.
主要成果:
- 在磁场为零的四面体石墨烯中观察了量子异常的哈尔状态在 ν = -1 和超导状态在 ν ≈ -3.5.
- 通过门电压证明量子异常哈尔状态的非挥发性切换.
- 在 ν = 2/3 的分数切尔恩绝缘体的识别与分数电荷.
- 通过整合过渡金属二甲基化层,而不会破坏量子异常霍尔态拓,形成一个新的超导口袋.
结论:
- 设计的石墨烯异构结构成功地在零磁场下共存量子异常霍尔和超导状态,克服了以前的障碍限制.
- 该系统允许调整和重新配置的拓边缘模式,为新的量子设备架构开辟了可能性.
- 这些发现使得超导和分量充电边缘模式之间的近距离合成为可能,进而推进拓量子物质的研究.
相关概念视频
01:24Superconductor
1.1K
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
1.1K
01:30The Hall Effect
2.2K
Edwin H. Hall, in the year 1879, devised an experiment that could be used to identify the polarity of the predominant charge carriers in a conducting material. From a historical perspective, this experiment was the first to demonstrate that the charge carriers in most metals are negative.
2.2K
01:28Types Of Superconductors
918
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
918
02:18Network Covalent Solids
13.3K
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
13.3K
01:17Theory of Metallic Conduction
1.3K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.3K
01:14π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
1.2K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
1.2K