Single and Multiphoton Optical Transitions in Atomically Thin Layers of Transition Metal Dichalcogenides

Abstract

The article discusses the production and properties of two-dimensional atomic layers of transition metal dichalcogenides (TMDs), focusing on the optical properties of monolayers. It begins with an introduction to the discovery of graphene production methods and the subsequent interest in TMDs. The basic properties of TMD monolayers, their crystal structure, and Brillouin zone are detailed. The article explores the energy spectrum of electrons in different valleys and the effective Hamiltonian describing states in parallel spin bands. The discussion extends to the matrix elements of interband optical transitions, including single-, two-, and three-photon transitions. Equations are provided to calculate probabilities of optical transitions, incorporating factors such as polarization vector, frequency of light, and temperature of the sample. Theoretical analysis of constituent matrix elements for these transitions is outlined, emphasizing quantum mechanical aspects. The article contributes researching of the optical behavior of transition metal dichalcogenides (TMDs) monolayers, particularly in structures with complex compositions.

Keywords

• polarized photon
• matrix element
• optical transitions
• two-band approximation
• current carriers
• electron hamiltonian
• momentum operator
• spin states