Frustrated S = 1/2 Chains in One-Dimensional Correlated Metal Ti4MnBi2

Electronic correlations lead to heavy quasiparticles in three-dimensional (3D) metals, and their collapse can destabilize magnetic moments. It is an open question whether there is an analogous instability in one-dimensional (1D) systems, unanswered due to the lack of metallic spin chain materials. We report neutron scattering measurements and Density Matrix Renormalization Group calculations establishing spinons in the correlated metal Ti ₄ MnBi ₂ , confirming that its magnetism is 1D. Ti ₄ MnBi ₂ is inherently frustrated, forming near a quantum critical point (QCP) separating different temperature T = 0 phases of the J ₁ - J ₂ XXZ model. 1D magnetism dominates to the lowest T , and is barely affected by weak interchain coupling. Ti ₄ MnBi ₂ is the first metallic spin chain where 3D conduction electrons become strongly correlated due to their coupling to 1D magnetic moments.