Proximal magnetometry of monolayers of magnetic moments

Characterizing two-dimensional superconductivity via nanoscale noise magnetometry with single-spin qubits

We propose nanoscale magnetometry via isolated single-spin qubits as a probe of superconductivity in two-dimensional materials. We characterize the magnetic field noise at the qubit location, arising from current and spin fluctuations in the sample and leading to measurable polarization decay of the qubit. We show that the noise due to transverse current fluctuations studied as a function of temperature and sample-probe distance can be used to extract useful information about the transition to a superconducting phase and the pairing symmetry of the superconductor. Surprisingly, at low temperat…

用于微电子电流高空间分辨率磁测量的自对准多层氮空位金刚石纳米颗粒

Self-aligned multilayered nitrogen vacancy diamond nanoparticles for high spatial resolution magnetometry of microelectronic currents

本文提出一种自对准多层氮空位金刚石纳米颗粒技术，通过层间NV中心取向对准实现微电子电流的高空间分辨率磁测量，并验证其对微线磁偶极子的ODMR检测能力。

Absence of ferromagnetism in VSe$_2$ caused by its charge density wave phase

How magnetism emerges in low-dimensional materials such as transition metal dichalcogenides at the monolayer limit is still an open question. Herein, we present a comprehensive study of the magnetic properties of single crystal and monolayer VSe$_{2}$, both experimentally and \emph{ab initio}. Magnetometry, X-ray magnetic circular dichrosim (XMCD) and \emph{ab initio} calculations demonstrate that the charge density wave in bulk stoichiometric VSe$_{2.0}$ causes a structural distortion with a strong reduction in the density of sates at the Fermi level, prompting the system towards a non-magnet…

Probing magnetism in 2D materials at the nanoscale with single spin microscopy

The recent discovery of ferromagnetism in 2D van der Waals (vdw) crystals has generated widespread interest, owing to their potential for fundamental and applied research. Advancing the understanding and applications of vdw magnets requires methods to quantitatively probe their magnetic properties on the nanoscale. Here, we report the study of atomically thin crystals of the vdw magnet CrI$_3$ down to individual monolayers using scanning single-spin magnetometry, and demonstrate quantitative, nanoscale imaging of magnetisation, localised defects and magnetic domains. We determine the magnetisa…

Spatiotemporal Mapping of Photocurrent in a Monolayer Semiconductor Using a Diamond Quantum Sensor

The detection of photocurrents is central to understanding and harnessing the interaction of light with matter. Although widely used, transport-based detection averages over spatial distributions and can suffer from low photocarrier collection efficiency. Here, we introduce a contact-free method to spatially resolve local photocurrent densities using a proximal quantum magnetometer. We interface monolayer MoS2 with a near-surface ensemble of nitrogen-vacancy centers in diamond and map the generated photothermal current distribution through its magnetic field profile. By synchronizing the photo…

Tuning the Optical Properties of an MoSe$_2$ Monolayer Using Nanoscale Plasmonic Antennas

Nanoplasmonic systems combined with optically-active two-dimensional materials provide intriguing opportunities to explore and control light-matter interactions at extreme sub-wavelength lengthscales approaching the exciton Bohr radius. Here, we present room- and cryogenic-temperature investigations of light-matter interactions between an MoSe$_2$ monolayer and individual lithographically defined gold dipole nanoantennas having sub-10 nm feed gaps. By progressively tuning the nanoantenna size, their dipolar resonance is tuned relative to the A-exciton transition in a proximal MoSe$_2$ monolaye…

A型范德华反铁磁体中的交换表面自旋波

Exchange Surface Spin Waves in Type-A van der Waals Antiferromagnets

研究A型范德华反铁磁体中体磁子带隙内的纯交换表面自旋波，发现其可由电磁波高效激发且杂散磁场具奇偶振荡特性。

Fe3O4纳米颗粒单层膜在超顺磁阻塞转变过程中涌现的超反铁磁关联

Emergent super-antiferromagnetic correlations in monolayers of Fe3O4 nanoparticles throughout the superparamagnetic blocking transition

该研究通过X射线共振磁散射发现Fe3O4纳米颗粒自组装体中存在颗粒间反铁磁关联，其强度随颗粒尺寸增大而增强，并在超顺磁阻塞转变中显著放大。

Observation of spin-wave characteristics in the two-dimensional ferromagnetic ordering of in-plane spins

The role of dipolar interactions and anisotropy are important to obtain, otherwise forbidden, ferromagnetic ordering at finite temperature for ions arranged in two-dimensional (2D) arrays (monolayers). Here we demonstrate that conventional low temperature magnetometry and polarized neutron scattering measurements can be performed to study ferromagnetic ordering of in-plane spins in 2D systems using a multilayer stack of non-interacting monolayers of gadolinium ions. The spontaneous magnetization is absent in the heterogenous magnetic phase observed here and the saturation value of the net magn…

基于邻近激子传感的二维半导体光学电压轮廓成像

Optical Voltage Profiling of 2D Semiconductors via Proximal Exciton Sensing

本研究提出基于邻近单层MoSe₂激子传感器的光学电压轮廓成像技术，可无创获取二维半导体器件的定量二维电压图，揭示了双层MoSe₂的金属-绝缘体转变及输运异质性。

Magnetic spin imaging under ambient conditions with sub-cellular resolution

Measuring spins is the corner stone of a variety of analytical techniques including modern magnetic resonance imaging (MRI). The full potential of spin imaging and sensing across length scales is hindered by the achievable signal-to-noise in inductive detection schemes. Here we show that a proximal Nitrogen-Vacancy (NV) ensemble serves as a precision sensing array. Monitoring its quantum relaxation enables sensing of freely diffusing and unperturbed magnetic ions in a microfluidic device. Multiplexed CCD acquisition and an optimized detection scheme enable direct spin noise imaging under ambie…

原子级薄层CrSBr中的纳米尺度磁性与磁相变

Nanoscale magnetism and magnetic phase transitions in atomically thin CrSBr

本文利用单自旋磁测量与直接磁成像，定量表征少层CrSBr的饱和磁化强度、磁各向异性常数及磁相变，揭示其微米尺度无缺陷磁相、单层空气稳定性及双层自旋翻转相界，为构筑奇异磁相和新型纳米磁器件奠定基础。