Tunable altermagnetism via interchain engineering in parallel-assembled atomic chains

Tunable altermagnetism via interchain engineering in parallel-assembled atomic chains

Deping Guo#, Canbo Zong#, Weihan Zhang, Cong Wang*, Junwei Liu*, and Wei Ji*

Altermagnetism has recently drawn considerable attention in three- and two dimensional materials. Here, we extend this concept to quasi-one-dimensional (Q1D) monolayers assembled from single-atomic magnetic chains. Through systematically examining nine types of structures, two stacking orders, and intra /inter-chain magnetic couplings, we identify four out of thirty promising structural prototypes for hosting altermagnetism, which yields 192 potential monolayer materials. We further confirm eight thermodynamically stable Q1D monolayers via high-throughput calculations. Using symmetry analysis and first-principles calculations, we find that the existence of altermagnetism is determined by the type of inter-chain magnetic coupling and predict three intrinsic altermagnets, CrBr3, VBr3, and MnBr3, due to their ferromagnetic inter-chain couplings and five extrinsic ones, CrF3, CrCl3, CrI3, FeCl3, and CoTe3, ascribed to their neglectable or antiferromagnetic inter-chain couplings. Moreover, the inter-chain magnetic coupling here is highly tunable by manipulating the inter-chain spacing, leading to experimentally feasible transitions between altermagnetic and nodal-line semiconducting states. In addition, applying external electric fields can further modulate the spin splitting. Our findings establish a highly tunable family of Q1D altermagnets, offering fundamental insights into the intricate relationship between geometry, electronic structure, and magnetism. These discoveries hold significant promises for experimental realization and future spintronic applications.

High-throughput discovery of thermodynamically stable 1D magnetic chains in transition-metal chalcogenides and halides

High-throughput discovery of thermodynamically stable 1D magnetic chains in transition-metal chalcogenides and halides

Canbo Zong#, Deping Guo#, Renhong Wang, Weihan Zhang, Jiaqi Dai, Zhongqin Zhang, Cong Wang*, Xianghua Kong, and Wei Ji*

The search for novel one-dimensional (1D) materials with exotic physical properties is crucial for advancing nanoelectronics and spintronics. Here, we perform a comprehensive high-throughput, first-principles study to explore the vast landscape of 1D transition-metal chalcogenides and halides. Starting with 6,832 candidate structures derived from 28 metals and 8 non-metals, we systematically evaluated their thermodynamic stability by comparing the formation energies of 1D chains against competing 2D phases, mimicking thermodynamic selectivity during nucleation. This screening identified 210 stable 1D magnetic chains. Furthermore, representation learning models revealed that chemical stoichiometry and the electron affinity of the non-metal element are key factors governing 1D stability. The stable materials exhibit a rich spectrum of properties, including diverse magnetic orders (FM, AFM) and Luttinger compensated antiferromagnetism in MnTe. We discovered 20 ferroelastic chains, with FeTe showing a giant magnetostriction of -5.57 %. Other emergent phenomena include Charge Density Wave (CDW) chains in FeTe and NiSe. Finally, our findings propose concrete platforms for quantum applications, such as the predicted realization of Majorana zero modes in a ferromagnetic CrCl2 chain on a superconducting NbSe2 substrate.

Robust High-Spin State in One-Dimensional CrX2 (X=Cl, Br, I) at the Single-Chain Limit

Robust High-Spin State in One-Dimensional CrX2 (X=Cl, Br, I) at the Single-Chain Limit

Yangjin Lee#, Linxuan Li#, Weihan Zhang#, Uje Choi, Kihyun Lee, Young-Min Kim, Wei Ji*, Wu Zhou*, Kwanpyo Kim*, and Alex Zettl*

Low-dimensional magnetic materials have garnered significant interest due to their unique physical properties and potential applications. Nevertheless, the synthesis of one-dimensional (1D) magnetic materials presents challenges, and the properties of these 1D materials at the single-chain limit have not been well investigated. We here explore experimentally and theoretically 1D CrX2 (X= Cl, Br, I) magnetic single-chains residing within carbon nanotubes. Single chains of CrX2 are confirmed by atomic-resolution scanning transmission electron microscopy imaging and spectroscopy analysis. Electron energy loss spectroscopy clearly reveals the high-spin state of Cr atoms within the chain. Notably, we present the first precise measurement and analysis of Cr spin state at the single-chain level, revealing that these spin states can be controlled by the local atomic bonding configuration (CrX2 versus CrX3 phases). Density functional theory calculations support the structural stability and provide the magnetic and electronic properties of the 1D CrX2 chains.

Semiregular tessellation of electronic lattices in untwisted bilayer graphene under anisotropic strain gradients

Semiregular tessellation of electronic lattices in untwisted bilayer graphene under anisotropic strain gradients

Zeyu Liu(刘泽宇)#, Xianghua Kong(孔祥华)#,*, Zhidan Li(李志聃), Zewen Wu(吴泽文), Linwei Zhou(周霖蔚), Cong Wang(王聪), and Wei Ji(季威)*

Low-dimensional magnetic materials have garnered significant interest due to their unique physical properties and potential applications. Nevertheless, the synthesis of one-dimensional (1D) magnetic materials presents challenges, and the properties of these 1D materials at the single-chain limit have not been well investigated. We here explore experimentally and theoretically 1D CrX2 (X= Cl, Br, I) magnetic single-chains residing within carbon nanotubes. Single chains of CrX2 are confirmed by atomic-resolution scanning transmission electron microscopy imaging and spectroscopy analysis. Electron energy loss spectroscopy clearly reveals the high-spin state of Cr atoms within the chain. Notably, we present the first precise measurement and analysis of Cr spin state at the single-chain level, revealing that these spin states can be controlled by the local atomic bonding configuration (CrX2 versus CrX3 phases). Density functional theory calculations support the structural stability and provide the magnetic and electronic properties of the 1D CrX2 chains.