Wei He
Associate Scientist, SLAC National Accelerator Laboratory
All Publications
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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
2024; 7 (1)
View details for DOI 10.1038/s42005-024-01753-z
View details for Web of Science ID 001282220500003
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Magnetically propagating Hund's exciton in van der Waals antiferromagnet NiPS3.
Nature communications
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
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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
2024; 8 (1)
View details for DOI 10.1103/PhysRevMaterials.8.014403
View details for Web of Science ID 001147553300005
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Stacking disorder in α-RuCl3 investigated via x-ray three-dimensional difference pair distribution function analysis
PHYSICAL REVIEW B
2023; 108 (14)
View details for DOI 10.1103/PhysRevB.108.144419
View details for Web of Science ID 001089582100004
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Electronic Character of Charge Order in Square-Planar Low-Valence Nickelates
PHYSICAL REVIEW X
2023; 13 (1)
View details for DOI 10.1103/PhysRevX.13.011021
View details for Web of Science ID 000936519600001
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Enhanced charge density wave with mobile superconducting vortices in La1.885Sr0.115CuO4.
Nature communications
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
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Freezing of the Lattice in the Kagome Lattice Heisenberg Antiferromagnet Zn-Barlowite ZnCu_{3}(OD)_{6}FBr.
Physical review letters
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
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Emergence of spin singlets with inhomogeneous gaps in the kagome lattice Heisenberg antiferromagnets Zn-barlowite and herbertsmithite
NATURE PHYSICS
2021
View details for DOI 10.1038/s41567-021-01310-3
View details for Web of Science ID 000681561600001
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Site-specific structure at multiple length scales in kagome quantum spin liquid candidates
PHYSICAL REVIEW MATERIALS
2020; 4 (12)
View details for DOI 10.1103/PhysRevMaterials.4.124406
View details for Web of Science ID 000600660300004
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Materializing rival ground states in the barlowite family of kagome magnets: quantum spin liquid, spin ordered, and valence bond crystal states
NPJ QUANTUM MATERIALS
2020; 5 (1)
View details for DOI 10.1038/s41535-020-0222-8
View details for Web of Science ID 000527641300002
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Enhancement and destruction of spin-Peierls physics in a one-dimensional quantum magnet under pressure
PHYSICAL REVIEW B
2018; 97 (5)
View details for DOI 10.1103/PhysRevB.97.054415
View details for Web of Science ID 000425090200002
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La-139 NMR investigation of the charge and spin order in a La1.885Sr0.115CuO4 single crystal
PHYSICAL REVIEW B
2018; 97 (6)
View details for DOI 10.1103/PhysRevB.97.064511
View details for Web of Science ID 000424967100006
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Synthesis dependent properties of barlowite and Zn-substituted barlowite
Journal of Solid State Chemistry
2018; 268: 123-129
View details for DOI 10.1016/j.jssc.2018.08.016
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Revisiting Cu-63 NMR evidence for charge order in superconducting La1.885Sr0.115CuO
PHYSICAL REVIEW B
2017; 96 (22)
View details for DOI 10.1103/PhysRevB.96.224508
View details for Web of Science ID 000418653500010