All Publications


  • Tilted stripes origin in La<sub>1.88</sub>Sr<sub>0.12</sub>CuO<sub>4</sub> revealed by anisotropic next-nearest neighbor hopping COMMUNICATIONS PHYSICS He, W., Wen, J., Jiang, H., Xu, G., Tian, W., Taniguchi, T., Ikeda, Y., Fujita, M., Lee, Y. S. 2024; 7 (1)
  • Magnetically propagating Hund's exciton in van der Waals antiferromagnet NiPS3. Nature communications He, W., Shen, Y., Wohlfeld, K., Sears, J., Li, J., Pelliciari, J., Walicki, M., Johnston, S., Baldini, E., Bisogni, V., Mitrano, M., Dean, M. P. 2024; 15 (1): 3496

    Abstract

    Magnetic van der Waals (vdW) materials have opened new frontiers for realizing novel many-body phenomena. Recently NiPS3 has received intense interest since it hosts an excitonic quasiparticle whose properties appear to be intimately linked to the magnetic state of the lattice. Despite extensive studies, the electronic character, mobility, and magnetic interactions of the exciton remain unresolved. Here we address these issues by measuring NiPS3 with ultra-high energy resolution resonant inelastic x-ray scattering (RIXS). We find that Hund's exchange interactions are primarily responsible for the energy of formation of the exciton. Measuring the dispersion of the Hund's exciton reveals that it propagates in a way that is analogous to a double-magnon. We trace this unique behavior to fundamental similarities between the NiPS3 exciton hopping and spin exchange processes, underlining the unique magnetic characteristics of this novel quasiparticle.

    View details for DOI 10.1038/s41467-024-47852-x

    View details for PubMedID 38664432

  • Local probe investigation of the spin dynamics in the kagome and interlayers of orthorhombic barlowite Cu<sub>4</sub>(OD)<sub>6</sub>FBr: <SUP>79</SUP>Br and <SUP>63</SUP>Cu NQR study PHYSICAL REVIEW MATERIALS Imai, T., Wang, J., Smaha, R. W., He, W., Wen, J., Lee, Y. S. 2024; 8 (1)
  • Stacking disorder in α-RuCl3 investigated via x-ray three-dimensional difference pair distribution function analysis PHYSICAL REVIEW B Sears, J., Shen, Y., Krogstad, M. J., Miao, H., Yan, J., Kim, S., He, W., Bozin, E. S., Robinson, I. K., Osborn, R., Rosenkranz, S., Kim, Y., Dean, M. M. 2023; 108 (14)
  • Electronic Character of Charge Order in Square-Planar Low-Valence Nickelates PHYSICAL REVIEW X Shen, Y., Sears, J., Fabbris, G., Li, J., Pelliciari, J., Mitrano, M., He, W., Zhang, J., Mitchell, J. F., Bisogni, V., Norman, M. R., Johnston, S., Dean, M. M. 2023; 13 (1)
  • Enhanced charge density wave with mobile superconducting vortices in La1.885Sr0.115CuO4. Nature communications Wen, J., He, W., Jang, H., Nojiri, H., Matsuzawa, S., Song, S., Chollet, M., Zhu, D., Liu, Y., Fujita, M., Jiang, J. M., Rotundu, C. R., Kao, C., Jiang, H., Lee, J., Lee, Y. S. 2023; 14 (1): 733

    Abstract

    Superconductivity in the cuprates is found to be intertwined with charge and spin density waves. Determining the interactions between the different types of order is crucial for understanding these important materials. Here, we elucidate the role of the charge density wave (CDW) in the prototypical cuprate La1.885Sr0.115CuO4, by studying the effects of large magnetic fields (H) up to 24 Tesla. At low temperatures (T), the observed CDW peaks reveal two distinct regions in the material: a majority phase with short-range CDW coexisting with superconductivity, and a minority phase with longer-range CDW coexisting with static spin density wave (SDW). With increasing magnetic field, the CDW first grows smoothly in a manner similar to the SDW. However, at high fields we discover a sudden increase in the CDW amplitude upon entering the vortex-liquid state. Our results signify strong coupling of the CDW to mobile superconducting vortices and link enhanced CDW amplitude with local superconducting pairing across the H-T phase diagram.

    View details for DOI 10.1038/s41467-023-36203-x

    View details for PubMedID 36759612

  • Freezing of the Lattice in the Kagome Lattice Heisenberg Antiferromagnet Zn-Barlowite ZnCu_{3}(OD)_{6}FBr. Physical review letters Wang, J., Yuan, W., Singer, P. M., Smaha, R. W., He, W., Wen, J., Lee, Y. S., Imai, T. 2022; 128 (15): 157202

    Abstract

    We use ^{79}Br nuclear quadrupole resonance (NQR) to demonstrate that ultraslow lattice dynamics set in below the temperature scale set by the Cu-Cu superexchange interaction J (≃160K) in the kagome lattice Heisenberg antiferromagnet Zn-barlowite. The lattice completely freezes below 50K, and ^{79}Br NQR line shapes become twice broader due to increased lattice distortions. Moreover, the frozen lattice exhibits an oscillatory component in the transverse spin echo decay, a typical signature of pairing of nuclear spins by indirect nuclear spin-spin interaction. This indicates that some Br sites form structural dimers via a pair of kagome Cu sites prior to the gradual emergence of spin singlets below 30K. Our findings underscore the significant roles played by subtle structural distortions in determining the nature of the disordered magnetic ground state of the kagome lattice.

    View details for DOI 10.1103/PhysRevLett.128.157202

    View details for PubMedID 35499891

  • Emergence of spin singlets with inhomogeneous gaps in the kagome lattice Heisenberg antiferromagnets Zn-barlowite and herbertsmithite NATURE PHYSICS Wang, J., Yuan, W., Singer, P. M., Smaha, R. W., He, W., Wen, J., Lee, Y. S., Imai, T. 2021
  • Site-specific structure at multiple length scales in kagome quantum spin liquid candidates PHYSICAL REVIEW MATERIALS Smaha, R. W., Boukahil, I., Titus, C. J., Jiang, J., Sheckelton, J. P., He, W., Wen, J., Vinson, J., Wang, S., Chen, Y., Teat, S. J., Devereaux, T. P., Das Pemmaraju, C., Lee, Y. S. 2020; 4 (12)
  • Materializing rival ground states in the barlowite family of kagome magnets: quantum spin liquid, spin ordered, and valence bond crystal states NPJ QUANTUM MATERIALS Smaha, R. W., He, W., Jiang, J., Wen, J., Jiang, Y., Sheckelton, J. P., Titus, C. J., Wang, S., Chen, Y., Teat, S. J., Aczel, A. A., Zhao, Y., Xu, G., Lynn, J. W., Jiang, H., Lee, Y. S. 2020; 5 (1)
  • Enhancement and destruction of spin-Peierls physics in a one-dimensional quantum magnet under pressure PHYSICAL REVIEW B Rotundu, C. R., Wen, J., He, W., Choi, Y., Haskel, D., Lee, Y. S. 2018; 97 (5)
  • La-139 NMR investigation of the charge and spin order in a La1.885Sr0.115CuO4 single crystal PHYSICAL REVIEW B Arsenault, A., Takahashi, S. K., Imai, T., He, W., Lee, Y. S., Fujita, M. 2018; 97 (6)
  • Synthesis dependent properties of barlowite and Zn-substituted barlowite Journal of Solid State Chemistry Smaha, R. W., He, W., Sheckelton, J. P., Wen, J., Lee, Y. S. 2018; 268: 123-129
  • Revisiting Cu-63 NMR evidence for charge order in superconducting La1.885Sr0.115CuO PHYSICAL REVIEW B Imai, T., Takahashi, S. K., Arsenault, A., Acton, A. W., Lee, D., He, W., Lee, Y. S., Fujita, M. 2017; 96 (22)