Frustrated magnetic materials, in which local conditions for energy minimization are incompatible because of the lattice structure, can remain disordered to the lowest temperatures. Such is the case for Ba(3)CuSb(2)O(9), which is magnetically anisotropic at the atomic scale but curiously isotropic on mesoscopic length and time scales. We find that the frustration of Wannier's Ising model on the triangular lattice is imprinted in a nanostructured honeycomb lattice of Cu(2+) ions that resists a coherent static Jahn-Teller distortion. The resulting two-dimensional random-bond spin-1/2 system on the honeycomb lattice has a broad spectrum of spin-dimer-like excitations and low-energy spin degrees of freedom that retain overall hexagonal symmetry.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1126/science.1212154 | DOI Listing |
Adv Mater
December 2024
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
Magnetoplumbites are one of the most broadly studied families of hexagonal ferrites, typically with high magnetic ordering temperatures, making them excellent candidates for permanent magnets. However, magnetic frustration is rarely observed in magnetoplumbites. Herein, the discovery, synthesis, and characterization of the first Mn-based magnetoplumbite, as well as the first magnetoplumbite involving pnictogens (Sb), ASbMnO (A = K or Rb) are reported.
View Article and Find Full Text PDFAdv Mater
December 2024
MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, China.
Lightweight cellular materials with high stiffness and excellent recoverability are critically important in structural engineering applications, but the intrinsic conflict between these two properties presents a significant challenge. Here, a topological cellular hierarchy is presented, designed to fabricate ultra-stiff (>10 MPa modulus) yet super-elastic (>90% recoverable strain) graphene aerogels. This topological cellular hierarchy, composed of massive corrugated pores and nanowalls, is designed to carry high loads through predominantly reversible buckling within the honeycomb framework.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, 430074 Wuhan, China.
The frustrated honeycomb spin model can stabilize a subextensively degenerate spiral spin liquid with nontrivial topological excitations and defects, but its material realization remains rare. Here, we report the experimental realization of this model in the structurally disorder-free compound GdZnPO. Using a single-crystal sample, we find that spin-7/2 rare-earth Gd^{3+} ions form a honeycomb lattice with dominant second-nearest-neighbor antiferromagnetic and first-nearest-neighbor ferromagnetic couplings, along with easy-plane single-site anisotropy.
View Article and Find Full Text PDFSmall
December 2024
Istituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche, Sede di Agrate Brianza, Via C. Olivetti 2, Agrate Brianza, I-20864, Italy.
Silicene, the analog of graphene composed of silicon atoms arranged in a honeycomb lattice, has garnered significant attention due to its unique properties, positioning it as a promising candidate for various applications in electronic devices, photovoltaics, photocatalysis, and biomedicals. While the chemical synthesis of silicene nanosheets has traditionally involved time-spending and expensive- methods, this study introduces a rapid vacuum/nitrogen cycle assisted (VANS) protocol that dramatically speeds up the production of silicene. The strategic implementation of vacuum/nitrogen cycles provides the efficient removal of the generated hydrogen, boosting the overall reaction kinetics while maintaining inert reaction conditions to prevent oxidation.
View Article and Find Full Text PDFPhys Rev E
November 2024
Department of Physics and National Institute of Science and Technology of Complex Systems, Federal University of Rio Grande do Norte, 59078-970 Natal-RN, Brazil.
This work establishes links between the Ising model and elliptic curves via Mahler measures. First, we reformulate the partition function of the Ising model on the square, triangular, and honeycomb lattices in terms of the Mahler measure of a Laurent polynomial whose variety's projective closure defines an elliptic curve. Next, we obtain hypergeometric formulas for the partition functions on the triangular and honeycomb lattices and review the known series for the square lattice.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!