Fermi polarons under strain-induced pseudomagnetic fields.

Abstract

Excitons in Transition Metal Dichalcogenides (TMDs) acquire a spin-like quantum number, a pseudospin, originating from the crystal's discrete rotational symmetry. Here, we break this symmetry using a tunable uniaxial strain, effectively generating a pseudomagnetic field acting on exciton valley degree of freedom. Under this field, we demonstrate pseudospin analogs of spintronic phenomena such as the Zeeman effect and Larmor precession and determine fundamental timescales for pseudospin dynamics in TMDs. Finally, we uncover the bosonic - as opposed to fermionic - nature of many-body excitonic species using the pseudomagnetic equivalent of the g-factor spectroscopy. Our work is the first step toward establishing this spectroscopy as a universal method for probing correlated many-body states and realizing pseudospin analogs of spintronic devices.