Spin dynamics in the triangular-lattice quantum antiferromagnet: a spinon-basis approach

GHIOLDI, ESTEBAN; MANUEL, LUIS O.; KAMIYA, YOSHITOMO; ZHANG, SHANG-SHUN; BATISTA, C.D.; GONZALEZ, MATIAS; TRUMPER, ADOLFO E.

Doshisha

Congreso; The Physical Society of Japan 2018 Autumn Meeting; 2018

The Physical Society of Japan

We compute the zero temperature dynamical structure factor S(q,ω) of the triangular lattice Heisenberg model using a Schwinger Boson approach that includes the Gaussian fluctuations (1/N correction) of the saddle point solution. While the ground state of this model exhibits a well-known 120 magnetic ordering, the excitation spectrum revealed by S(q,ω) has a strong quantum character, which is not captured by low-order 1/S expansions. The low-energy energy magnons consist of two spinon bound states confined by the gauge fluctuations of the auxiliary field. This composite nature of the magnons leads to an internal structure of the magnon peaks. In addition, the continuum of high-energy spinon modes extends up to three times the single-magnon bandwidth.