Dimensional reduction and incommensurate dynamic correlations in the <math xmlns="http://www.w3.org/1998/Math/MathML"> <mi>S</mi> <mo>=</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </math> triangular-lattice antiferromagnet Ca<sub>3</sub>ReO<sub>5</sub>Cl<sub>2</sub>.

Zvyagin, S A; Ponomaryov, A N; Wosnitza, J; Hirai, D; Hiroi, Z; Gen, M; Kohama, Y; Matsuo, A et al. · Nat Commun · 2022

basic_science · Level V

Where this comes from

Abstract

The observation of spinon excitations in the S = 1 2 triangular antiferromagnet Ca3ReO5Cl2 reveals a quasi-one-dimensional (1D) nature of magnetic correlations, in spite of the nominally 2D magnetic structure. This phenomenon is known as frustration-induced dimensional reduction. Here, we present high-field electron spin resonance spectroscopy and magnetization studies of Ca3ReO5Cl2, allowing us not only to refine spin-Hamiltonian parameters, but also to investigate peculiarities of its low-energy spin dynamics. We argue that the presence of the uniform Dzyaloshinskii-Moriya interaction (DMI) shifts the spinon continuum in momentum space and, as a result, opens a zero-field gap at the Γ point. We observed this gap directly. The shift is found to be consistent with the structural modulation in the ordered state, suggesting this material as a perfect model triangular-lattice system, where a pure DMI-spiral ground state can be realized.