posted on 2022-01-20, 11:43authored bySamuel Brem, Ermin Malic
The strong Coulomb
interaction in monolayer semiconductors represents
a unique opportunity for the realization of Wigner crystals without
external magnetic fields. In this work, we predict that the formation
of monolayer Wigner crystals can be detected by their terahertz response
spectrum, which exhibits a characteristic sequence of internal optical
transitions. We apply the density matrix formalism to derive the internal
quantum structure and the optical conductivity of the Wigner crystal
and to microscopically analyze the multipeak shape of the obtained
terahertz spectrum. Moreover, we predict a characteristic shift of
the peak position as a function of charge density for different atomically
thin materials and show how our results can be generalized to an arbitrary
two-dimensional system.