Self-energy of phonons in a chiral quantum spin liquid background

Abstract

Quantum spin liquids (QSLs) are defined as spin systems lacking magnetic order down to the lowest temperature. This indirect definition makes it difficult to identify what properties to look out for in identifying them experimentally. Here, we assume the system contains one and identify how it influences the dynamics of phonons. Identifying how phonons interact with a QSL background may provide a description of what signals to look for when trying to observe the said QSL. We found that in a chiral QSL background, the phonons experience negative second-order energy shifts when their momenta coincide with the high-energy spinon momenta; meanwhile in a π-flux QSL background—which is a limiting case of the chiral QSL background—the phonons experience negative second-order energy shifts when their momenta coincide with the low-energy spinon momenta.