The effect of magnetic order on longitudinal Tomonaga-Luttinger liquid spin dynamics in weakly coupled spin-1 2 chains

Journal article

The quantum many-body interactions in one-dimensional spin- 1 2 systems are subject to Tomonaga-Luttinger liquid (TLL) physics, which predict an array of multi-particle excitations that form continua in momentum-energy space. Here we use inelastic neutron spectroscopy to study the TLL spin dynamics in SrCo2V2O8, a compound which contains weakly coupled spin- 1 2 chains of Co atoms, at 0.05 K and in a longitudinal magnetic field up to 9.0 T. The measurements were performed above 3.9 T, where the ground state N´eel antiferromagnetic (AFM) order is completely suppressed, and the multi-particle excitations are exclusively of TLL type. In this region and below 7.0 T, the longitudinal TLL mode – psinon/antipsinon (P/AP) – is unexpectedly well described by a damped harmonic oscillator (DHO) while approaching the zone center defining the static spin-spin correlations. A non-DHO-type, continuum-like signal is seen at higher fields, but deviations from the ideal one-dimensional TLL still remain. This change in the P/AP mode coincides with the phase transition between the longitudinal spin density wave (LSDW) and transverse AFM order. Inside the LSDW state, the DHO-type P/AP spectral weight increases and the linewidth broadens as the magnetic order parameter decreases. These results reveal the impact of three-dimensional magnetic order on the TLL spin dynamics; they call for beyond the mean-field treatment for the interchain exchange interactions.

Authors: Shen, L; Alshemi, A; Campillo, E; Blackburn, E; Steffens, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B
• Volume: 107
• Article number: 134425
• Publication date: 2023-04-20
• Acceptance date: 2023-04-06
• DOI: 10.1103/PhysRevB.107.134425
• EISSN: 1550-235X
• ISSN: 1098-0121
• Language: English
• Keywords: FFR