Electron solids in two-dimensional semiconductor heterostructures

Atomically thin two-dimensional (2D) semiconductors and heterostructures offer an exciting platform for the study of tunable correlated electronic phenomena. The interaction between electrons in 2D semiconductors can be adjusted by manipulating the electron density and confinement potential, leading to the formation of various electron solid phases. When electrons are confined within a moire superlattice, a periodic array of few-electron Wigner molecules can be created. When electrons are confined within domain walls, we can observe the evolution of a 1D Wigner crystal into a weakly interacting Luttinger liquid, with the emergence of a dimerized crystal in the intermediate region. In a plain 2D semiconductor without confinement, a disordered Wigner solid is observed at low density. As the electron density increases, the Wigner solid undergoes a melting transition into a mixed phase, characterized by the coexistence of electron solid and fluid regions. This behavior can be understood within the microemulsion model.