Spin-resolved imaging of atomic-scale helimagnetism in mono- and bi-layer NiI2

Spin-resolved imaging of atomic-scale helimagnetism in mono- and bi-layer NiI2

Mao-Peng Miao, Nanshu Liu, Wen-Hao Zhang, Jian-Wang Zhou, Dao-Bo Wang, Cong Wang, Wei Ji, and Ying-Shuang Fu

Noncollinear magnetic orders in monolayer van der Waals magnets are crucial for probing delicate magnetic interactions under minimal spatial constraints and advancing miniaturized spintronic devices. Despite their significance, achieving atomic-scale identification remains challenging. In this study, we utilized spin-polarized scanning tunneling microscopy and density functional theory calculations to identify spin-spiral orders in mono- and bi-layer NiI2, grown on graphene-covered SiC(0001) substrates. We discovered two distinct spin-spiral states with Q vectors aligning and deviating by 7° from the lattice direction, exhibiting periodicities of 4.54 and 5.01 times the lattice constant, respectively. These findings contrast with bulk properties and align closely with our theoretical predictions. Surprisingly, the finite sizes of monolayers induce incommensurability with the spin-spiral period, facilitating collective spin switching behavior under magnetic fields. Our research reveals intrinsic noncollinear magnetism at the monolayer limit with unprecedented resolution, paving the way for exploring novel spin phenomena.

六名成员参加“第四届团簇科学与原子制造学术研讨会”

六名成员参加“第四届团簇科学与原子制造学术研讨会”

2023年4月21-23日,中国人民大学物理学院季威教授携刘南舒博士后以及郭的坪、伍琳璐、官雨柔、戴佳琦等四名博士生赴西安参加了第四届“团簇科学与原子制造学术研讨会”。季威教授受会议主办方邀请作了题为“低维超原子晶体中的特殊电子态”的报告。

季威教授在作报告

刘南舒、郭的坪、伍琳璐、官雨柔、戴佳琦等成员分别在会议中展示了题为 “Magnetic coupling in superatom Mn@Sn12 assembly” (Liu), “Controllable dimensionality conversion between 1D and 2D CrCl3 magnetic nanostructures” (Guo), “Interweaving Polar Charge Orders in a Layered Metallic Superatomic Crystal” (Wu), “Magnetization-distance oscillation induced by competing interactions in Cr doped Au6Te12Se8 superatomic assembly” (Guan) 和“One-Step Exfoliation Method for Plasmonic Activation of Large-Area 2D Crystals” (Dai) 的墙报,均获得会议主办方颁发的优秀墙报奖状。

(左图)不愿透露样貌的郭师姐和她的墙报;(右图)伍琳璐和戴佳琦在她们的墙报前合影

第四届“团簇科学与原子制造学术研讨会”由西安交通大学物理学院物质非平衡合成与调控教育部重点实验室、南京大学物理学院和大连理工大学三束材料改性教育部重点实验室联合主办;西安交通大学激光与粒子束科学技术研究所承办。会议主题是交流近年来原子与分子及团簇物理、原子制造和纳米科技方面的研究进展,探讨本领域的未来发展方向。季威研究组成员为参与本次会议做了充分准备,并期待下次参会的科研成果能有在团簇及原子制造领域有新的突破。

Two-Dimensional Magnetic Semiconducting Heterostructures of Single-Layer CrI3–CrI2

Two-Dimensional Magnetic Semiconducting Heterostructures of Single-Layer CrI3–CrI2

ACS Appl. Mater. Interfaces 15, 19574–19581 (2023)

Peigen Li, Nanshu Liu, Jihai Zhang, Shenwei Chen, Xuhan Zhou, Donghui Guo, Cong Wang, Wei Ji, and Dingyong Zhong

Single-layer heterostructures of magnetic materials are unique platforms for studying spin-related phenomena in two dimensions (2D) and have promising applications in spintronics and magnonics. Here, we report the fabrication of 2D magnetic lateral heterostructures consisting of single-layer chromium triiodide (CrI3) and chromium diiodide (CrI2). By carefully adjusting the abundance of iodine based on molecular beam epitaxy, single-layer CrI3–CrI2 heterostructures were grown on Au(111) surfaces with nearly atomic-level seamless boundaries. Two distinct types of interfaces, i.e., zigzag and armchair interfaces, have been identified by means of scanning tunneling microscopy. Our scanning tunneling spectroscopy study combined with density functional theory calculations indicates the existence of spin-polarized ground states below and above the Fermi energy localized at the boundary. Both the armchair and zigzag interfaces exhibit semiconducting nanowire behaviors with different spatial distributions of density of states. Our work presents a novel low-dimensional magnetic system for studying spin-related physics with reduced dimensions and designing advanced spintronic devices.

DOI: 10.1021/acsami.2c22494

刘南舒 博士Liu, Nanshu (Dr.)

刘南舒 博士
Liu, Nanshu (Dr.)

刘南舒,西南大学物理科学与技术学院 副教授

电子邮箱:liuns0215@swu.edu.cn
URL: 刘南舒 – 西南大学物理科学与技术学院

教育经历

(1) 2016-09至2021-06,大连理工大学,凝聚态物理,博士

(2) 2012-09至2016-06,西北师范大学,物理学,学士

工作经历

2021-09至2024-06,中国人民大学物理学系,博士后
2024-09至今,西南大学物理科学与技术学院,讲师/副教授

研究方向

利用密度泛函理论探索低维材料的磁性、电极化等新奇物性及其合理调控。

Selected Publications (代表性论文)

(1) Nanshu Liu*, Cong Wang, Wei Ji*, Recent research advances in two-dimensional magnetic materials, Acta Phys. Sinica 71, 127504 (2022)

(2) Nanshu Liu, Si Zhou*, Jijun Zhao, Photoinduced spin injection and ferromagnetism in 2D group III monochalcogenides, J. Phys. Chem. Lett. 153, 590 (2022)

(3) Nanshu Liu, Si Zhou*, Jijun Zhao, Visible-light overall water splitting on g-C3N4 decorated by subnanometer oxide clusters, Mater. Today Phys., 16, 100312 (2021)

(4) Nanshu Liu, Yanyan Zhao, Si Zhou*, Jijun Zhao, CO2 reduction on p-block metal oxide overlayers on metal substrates—2D MgO as a prototype, J. Mater. Chem. A, 8, 5688 (2020)

(5) Nanshu Liu, Si Zhou*, Jijun Zhao, High-Curie-temperature ferromagnetism in bilayer CrI3 on bulk semiconducting substrates, Phys. Rev. Mater., 4, 094003 (2020)

(6) Nanshu Liu, Junfeng Zhang*, Si Zhou*, Jijun Zhao, Tuning the electronic properties of bilayer black phosphorene with the twist angle, J. Mater. Chem. C, 8, 6264 (2020)

(7) Shaofeng Li#, Yan Zhang#, Nanshu Liu#, et. al, Operando revealing dynamic reconstruction of NiCo carbonate hydroxide for high-rate energy storage, Joule, 4, 673 (2020)