Please join us on Monday May 27th, from 11:00am-12:00pm in GSB 306 for Jean-Sébastien Bernier’s seminar on Repulsively Bound Magnon Excitations of a Spin-1/2 XXZ Chain in a Staggered Transverse Field.

Physics Department Seminar

Jean-Sébastien Bernier
University of Northern British Columbia

Monday May 27th, 2024
11:00am – 12:00pm, Room: GSB 306

Repulsively Bound Magnon Excitations of a Spin-1/2 XXZ Chain in a Staggered Transverse Field
Motivated by the chain antiferromagnet BaCo2V208, we study the excitation spectrum of the one-dimensional spin-1/2 XXZ chain with antiferromagnetic Ising anisotropy across a magnetic quantum phase transition induced by the application of a site-dependent transverse magnetic field. Considering a situation where the transverse magnetic field has a strong uniform component and a weaker staggered part, we determine the nature of the excitations giving rise to the spin dynamical structure factor using a combination of analytical approaches and the numerically exact time-dependent matrix product state method. Below the quantum phase transition, we identify high-energy many-body two-magnon and three-magnon repulsively bound states which are clearly visible due to the staggered component of the magnetic field. At high magnetic fields and low temperature, single magnons dominate the dynamics. These results are in very good agreement with terahertz spectroscopy measurements.