Raymond Ashoori

Research

The Ashoori group studies interacting electronic systems in low dimensional (0,1 or 2 dimensions) electronic structures, such as semiconductor samples, graphene, and transition-metal dichalcogenide layers. The Ashoori group has developed a novel pulsed method that allows contactless measurement of electron tunneling spectra in isolated conducting and even insulating samples. This method, for instance, permitted the discovery of a sharp feature in tunneling spectra originating from the vibrations of an electronic crystal. The Ashoori group also uses very sensitive capacitance measurements for study of novel electronic systems. In collaboration with the Jarillo-Herrero group, these measurements detected spectral features from the Hofstadter Butterfly in graphene and correlated insulating states of twisted bilayer graphene.The Ashoori group’s measurement methods have sufficient sensitivity to determine spectra for single electron additions to small isolated structures such as quantum dots. While simple quantum mechanical calculations determine the motion of a single electron in such a confining structures, it is far from simple to understand the behavior of many trapped electrons. Not only do the electrons repel one another, they are indistinguishable. This fact, along with the principle that only one electron can exist in any quantum mechanical orbit, produces unusual and sometimes counterintuitive correlations in the motions of electrons.