Exploring Short-Range Correlations with Diffuse Neutron Scattering

by Dr Jennifer Graham (Institut Laue-Langevin and University of Birmingham)

Friday 7 Jul 2023, 15:00 → 16:00 Europe/Zurich

SZ-WBGB/019

Quantum materials are a broad class of systems that exhibit many unusual and exotic phenomena, and may have applications in quantum computers, quantum sensing and high-temperature superconductors [1]. These phenomena are brought on by the complex, short-range correlations acting between different moment pairs within the system. As such the correlations give rise to broad diffuse features in neutron scattering that can be understood through local structure methods, such as reverse Monte Carlo analysis. One particularly enigmatic quantum magnetic ground state is the spiral spin liquid, which is composed of a macroscopically degenerate manifold of fluctuating spin spirals [2,3]. Experimental realizations of the spiral spin liquid are scarce, mainly due to the prominence of structural distortions in candidate materials that can trigger order-by-disorder transitions to more conventionally ordered magnetic ground states. Expanding the pool of candidate materials that may host a spiral spin liquid is therefore crucial to realizing this novel magnetic ground state and understanding its robustness against perturbations that arise in real materials. Here, I show that the material LiYbO₂ [3,4] is the first experimental realization of a spiral spin liquid predicted to emerge from the J₁−J₂ Heisenberg model on an elongated diamond lattice [5]. Through a complementary combination of high-resolution and diffuse neutron magnetic scattering studies on a polycrystalline sample, I demonstrate that LiYbO₂ fulfils the requirements for the experimental realization of the spiral spin liquid and reconstruct single-crystal diffuse neutron magnetic scattering maps that reveal continuous spiral spin contours — a characteristic experimental hallmark of this exotic magnetic phase.

References
[1]  L. Clark and A. H. Abdeldaim, Ann. Rev. Mater. Res. 51: 495-519 (2021)
[2] X.-P. Yao et al. Front. Phys. 16 53303 (2021)
[3] M. M. Bordelon et al. Phys. Rev. B. 103, 014420 (2021)
[4] E. M. Kenney et al. Phys. Rev. B. 106, 144401 (2022)
[5] J. N. Graham et al. Phys. Rev. Lett. 130 166703 (2023)