Spin Dynamics of the Elemental Quantum Spin Liquid β-Mn*

Pure β-Mn is the only elemental metal that shows quantum spin-liquid-like behavior [1]. Its magnetic Mn atoms occupy a frustrated three-dimensional network of corner-sharing triangles. Unlike all other transition metals, β-Mn does not show long-range magnetic order to the lowest measured temperatures (~0.3 K). Instead, its magnetic response is dominated by strong antiferromagnetic spin fluctuations that persist up to room temperature and exhibit non-Fermi-liquid scaling [2].

We present neutron-scattering measurements of the spin dynamics of β-Mn over a wide range of momentum transfer, energy transfer, and temperature. Our measurements allow us to parameterize an effective Hamiltonian [3] that reveals the temperature dependence of the on-site magnetic moment and the magnetic interactions. Our results shed new light on the unusual magnetic behaviour of this remarkable element and demonstrate an experiment-driven approach to parameterizing magnetic interactions in metals.

[1] H. Nakamura et al., J. Phys. Condens. Matter 9, 4701 (1997).
[2] J. R. Stewart et al., Phys. Rev. Lett. 89, 186403 (2002).
[3] J. A. M. Paddison et al., Phys. Rev. Lett. 110, 267207 (2013).