PhD position: Interacting electrons in atomically thin semiconductors

Single atomically thin planes of layered transition metal dichalcogenides such as MoS2 have recently been discovered to be two-dimensional semiconductors with direct bandgaps. Because of their atomically thin nature, electronic screening in these materials is poor, and electron-electron and electron-impurity interactions are unusually strong. The interaction strength is also tunable through changing the surrounding dielectric environment, impossible in conventional semiconductors. This PhD project will experimentally probe the effect of strong electron-electron and electron-impurity interaction in MoS2. In the Fuhrer laboratory at Monash MoS2 devices will be fabricated using lithographic techniques and transferred into ultra-high vacuum (UHV) where they will be studied with in situ electronic transport measurements and low-temperature scanning probe microscopy capable of imaging their atomic structure. Dopants such as alkali metals will be controllably placed on MoS2 and the screening cloud of individual dopant atoms will be imaged at the atomic scale. The effect of dopants on electronic transport properties will be measured directly. Electron-electron interactions will be controlled through the choice of substrate dielectric constant, and the effect on electronic and optical properties will be studied. Low-temperature scanning probe microscopy will be used to search for signatures of exotic interaction-driven physics such as Wigner crystallization at low carrier densities.