Xiang Xu#, Pengbin Liu#, Cong Wang#, Yudi Dai#, Bin Cheng#, Yan Jiang#, Hao Luo, Jinsong Wu, Shi-Jun Liang, Wei Ji*, Feng Miao*, Tianyou Zhai*, and Xing Zhou*
Abstract:
Two-dimensional (2D) lateral magnetic heterostructures offer a promising platform for exploring interfacial magnetism and related physical phenomena. Current synthesis strategies primarily rely on sequential edge-epitaxy. However, the second-step chemical vapor deposition process inevitably introduces various interfacial defects, disrupting the intrinsic magnetic properties. Here we propose an interface-driven endotaxy method that enables the synthesis of 2D lateral magnetic heterostructures (e.g., CuCrSe2, CuCr2Se4, AgCrSe2-CrSe2, CuCrS2-CuCr2S4) with atomically sharp interfaces. The growth of the second phase is triggered by a controlled interfacial phase transition, as revealed by in situ imaging of the growth, systematic microstructure characterizations, and theoretical calculations. The obtained heterointerfaces feature coherent lattice and symmetry breaking, leading to unique magnetic phenomena such as proximity-induced ferromagnetism near the interface and the topological Hall effect in CuCrSe2-CuCr2Se4. Moreover, in AgCrSe2-CrSe2, the synthesized CrSe2 exhibits a previously unreported defect spinel structure and room-temperature ferromagnetism at the heterointerface. The interface-driven endotaxy growth method opens a rational pathway for fabricating 2D lateral magnetic heterostructures, providing a robust material platform for fundamental studies and the development of magnetoelectronic and spintronic devices.
Kuakua Lu#, Yun Li#,*, Qijing Wang#,* Linlu Wu#, Xinglong Ren, Xu Chen, Luhao Liu, Yating Li, Xiaoming Xu, Qingkai Zhang, Di Wang, Liqi Zhou, Mingfei Xiao, Sai Jiang, Mengjiao Pei, Haoxin Gong, William Wood, Ian E. Jacobs, Junzhan Wang, Gang Chen, Peng Wang, Zhaosheng Li, Chunfeng Zhang, Xinran Wang, Xu Wu, Yeliang Wang, Wei Ji, Songlin Li, Jingsi Qiao*, Yi Shi*, Henning Sirringhaus*
Abstract:
In single-crystal silicon metallic charge transport of field-induced carriers can be observed over a wide temperature range. Such behavior is rare in undoped organic semiconductors but important for fundamental understanding and engineering devices with advanced performance. Here, we report a metallic charge transport down to 8 K with a record-high electrical conductivity of 245 S cm−1 and a Hall mobility > 100 cm2 V−1 s−1 at 20 K in a two-dimensional, molecular crystal bilayer. We infer that this unique transport behavior originates from the phenyl bridge coupling between the two molecular layers, which suppresses molecular vibrations and weakens Coulomb interactions. We develop a controlled method for introducing defects, which allows the first observation of a disorder-driven metal-insulator transition in a molecular crystal. Our work demonstrates that exceptional charge transport properties can be attained in a molecular bilayer system with phenyl bridges, providing new incentives for exploring the molecular design space in this class of compounds more broadly.
Li Huang, Yuqing Xing, Qi Zheng, Senhao Lv, Lan Chen, Hui Chen, Haitao Yang, Wei Ji and Hong-Jun Gao*
Abstract:
Altermagnetic materials, with real-space antiferromagnetic arrangement and reciprocal-space anisotropic spin splitting, have attracted much attention. However, the spin splitting is small in most altermagnetic materials, which is a disadvantage to their application in electronic devices. In this study, based on symmetry analysis and the first-principles electronic structure calculations, we predict for the first time two Luttinger compensated bipolarized magnetic semiconductors Mn(CN)2 and Co(CN)2 with isotropic spin splitting as in the ferromagnetic materials. Our further analysis shows that the Luttinger compensated magnetism here depends not only on spin group symmetry, but also on the crystal field splitting and the number of d-orbital electrons. In addition, the polarized charge density indicates that both Mn(CN)2 and Co(CN)2 have the quasi-symmetry T{tau} , resulting from the crystal field splitting and the number of d-orbital electrons. The Luttinger compensated magnetism not only has the zero total magnetic moment as the antiferromagnetism, but also has the isotropic spin splitting as the ferromagnetism, thus our work not only provides theoretical guidance for searching Luttinger compensated magnetic materials with distinctive properties, but also provides a material basis for the application in spintronic devices.
Peng-Jie Guo, Xiao-Yao Hou, Ze-Feng Gao, Huan-Cheng Yang, Wei Ji, Zhong-Yi Lu
Abstract:
Altermagnetic materials, with real-space antiferromagnetic arrangement and reciprocal-space anisotropic spin splitting, have attracted much attention. However, the spin splitting is small in most altermagnetic materials, which is a disadvantage to their application in electronic devices. In this study, based on symmetry analysis and the first-principles electronic structure calculations, we predict for the first time two Luttinger compensated bipolarized magnetic semiconductors Mn(CN)2 and Co(CN)2 with isotropic spin splitting as in the ferromagnetic materials. Our further analysis shows that the Luttinger compensated magnetism here depends not only on spin group symmetry, but also on the crystal field splitting and the number of d-orbital electrons. In addition, the polarized charge density indicates that both Mn(CN)2 and Co(CN)2 have the quasi-symmetry T{\tau} , resulting from the crystal field splitting and the number of d-orbital electrons. The Luttinger compensated magnetism not only has the zero total magnetic moment as the antiferromagnetism, but also has the isotropic spin splitting as the ferromagnetism, thus our work not only provides theoretical guidance for searching Luttinger compensated magnetic materials with distinctive properties, but also provides a material basis for the application in spintronic devices.
Two‑dimensional multiferroics promise low‑power, multifunctional devices, yet the intrinsic coexistence and mutual control of three coupled ferroic orders in a single layer remains elusive. Here, we identify pentagonal monolayer FeO2 as an intrinsic triferroic altermagnet where ferroelectric (FE), ferroelastic (FA), and altermagnetic (AM) orders coexist and tightly coupled, accompanied by a competing antiferroelectric (AFE) phase using first‑principles calculations. The solely presence of glide mirror Mx symmetry in a FeO2 sublayer, with the breaking of four‑fold rotation C4z symmetry, induces in‑plane vector ferroelectricity and twin‑related ferroelastic strains. Both FE and AFE phases break combined parity–time symmetry and display sizable altermagnetic spin splitting with Néel temperatures over 200 K. Electric‑field induced rotation of the FE polarization reverses the sign of the spin splitting, while in‑plane uniaxial strain triggers ferroelastic switching that simultaneously rotates the FE polarization vector by 90° and reverses the AM state. These electric‑field‑ and strain‑mediated pathways interlink six distinct polarization states that can be selected purely by electric fields and/or mechanical strain. This work extends intrinsic triferroicity to pentagonal monolayers and outlines a symmetry‑based route toward mechanically and electrically configurable altermagnetic spintronics.
