The newly-discovered chromium-based kagome metal CsCr3Sb5 has garnered significant interest due to its strong electron correlations, intertwined orders and potential for unconventional superconductivity under high pressure. However, the nature of superconducting and magnetic interactions during the transition from the parent compound CsV3Sb5 to CsCr3Sb5 remains elusive. Here, we report the discovery of spatially anisotropic Kondo resonance which intertwines with the superconducting gap, facilitated by the introduction of magnetic Cr impurities into the kagome superconductor CsV3Sb5. In addition to the gradual suppression of long-ranged charge-density-wave orders, dilute Cr dopants induce local magnetic moments, giving rise to the emergence of Kondo resonances. In addition, the Kondo resonance forms spatially anisotropic ripple-like structures around the Cr dopants, breaking all local mirror symmetries. This anisotropy arises from the antiferromagnetic coupling between itinerant electrons and the Cr-induced spin-up electrons. Remarkably, as the Kondo screening develops, the coherence peak and depth of superconducting gap with finite zero-energy conductance significantly enhances. It indicates that non-superconducting pairs at the Fermi surface in the parent compound participate in the Kondo effect, effectively screening the magnetic moments of Cr dopants while simultaneously enhancing the superfluid density. Our findings pave a unique pathway for exploring the interplay between superconductivity and local magnetic moments in kagome systems.
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.
Xiangqi Wang†, Cong Wang†, Yupeng Wang†, Chunhui Ye, Azizur Rahman, Min Zhang, Suhan Son, Jun Tan*, Zengming Zhang*, Wei Ji*, Je-Geun Park6,7,8, and Kai-Xuan Zhang†*
Abstract:
Van der Waals (vdW) magnets, with their two-dimensional (2D) atomic structures, provide a unique platform for exploring magnetism at the nanoscale. Although there have been numerous reports on their diverse quantum properties, the emergent interfacial magnetism— artificially created at the interface between two layered magnets—remains largely unexplored. This work presents observations of such emergent interfacial magnetism at the ferromagnet/antiferromagnet interface in a vdW heterostructure. We report the discovery of an intermediate Hall resistance plateau in the anomalous Hall loop, indicative of emergent interfacial antiferromagnetism fostered by the heterointerface. This plateau can be stabilized and further manipulated under varying pressures but collapses under high pressures over 10 GPa. Our theoretical calculations reveal that charge transfer at the interface is pivotal in establishing the interlayer antiferromagnetic spin-exchange interaction. This work illuminates the previously unexplored emergent interfacial magnetism at a vdW interface comprised of a ferromagnetic metal and an antiferromagnetic insulator, and highlights its gradual evolution under increasing pressure. These findings enrich the portfolio of emergent interfacial magnetism and pave the way for future investigations on vdW magnetic interfaces and the development of next-generation spintronic devices.
Two-dimensional room-temperature ferromagnet CrTe2 is a promising candidate material for spintronic applications. However, its large-scale and cost-effective synthesis remains a challenge. Here, we report the fine controllable synthesis of wafer-scale 1T-CrTe2 films on a SiO2/Si substrate using plasma-enhanced chemical vapor deposition at temperatures below 400 ºC. Magnetic hysteresis measurements reveal that the synthesized 1T-CrTe2 films exhibit perpendicular magnetic anisotropy along with distinct step-like magnetic transitions. We find that 1T-CrTe2 is susceptible to oxygen adsorption even in ambient conditions. Our theoretical calculations indicate that the oxidation of surface layers is crucial for the absence of out-of-plane easy axis in few-layer CrTe2, while the interlayer antiferromagnetic coupling among the upper surface layers leads to the observed step-like magnetic transitions. Our study provides a Si-CMOS compatible approach for the fabrication of magnetic two-dimensional materials and highlights how unintentional adsorbents or dopants can significantly influence the magnetic behaviors of these materials.
Interlayer coupling plays a critical role in tuning the electronic structures and magnetic ground states of two-dimensional materials, influenced by the number of layers, interlayer distance, and stacking order. However, its effect on the orientation of the magnetic easy axis remains underexplored. In this study, we demonstrate that interlayer coupling can significantly alter the magnetic easy-axis orientation, as shown by the magnetic easy-axis of monolayer 1T-MnSe2 tilting 33° from the z-axis, while aligning with the z-axis in the bilayer. This change results from variations in orbital occupations near the Fermi level, particularly involving nonmetallic Se atoms. Contrary to the traditional focus on magnetic metal atoms, our findings reveal that Se orbitals play a key role in influencing the easy-axis orientation and topological Chern numbers. Furthermore, we show that the occupation of Se p-orbitals, and consequently the magnetic anisotropy, can be modulated by factors such as stacking order, charge doping, and external strain. Our results highlight the pivotal role of interlayer coupling in tuning the magnetic properties of layered materials, with important implications for spintronic applications.
