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Full-Text Articles in Physics
Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon
Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon
Senior Theses
Two-dimensional materials exhibit properties unlike anything else seen in conventional substances. Electrons in these materials are confined to move only in the plane. In order to explore the effects of these materials, we have built apparatus and refined procedures with which to create two-dimensional structures. Two-dimensional devices have been made using exfoliated graphene and placed on gold contacts. Their topography has been observed using Atomic Force Microscopy (AFM) confirming samples with monolayer, bilayer, and twisted bilayer structure. Relative work functions of each have been measured using Kelvin Probe Force Microscopy (KPFM) showing that twisted bilayer graphene has a surface potential …
Enhanced Flexoelectricity At Reduced Dimensions Revealed By Mechanically Tunable Quantum Tunnelling, Saikat Das, Bo Wang, Tula R. Paudel, Sung Min Park, Evgeny Y. Tsymbal, Long-Qing Chen, Daesu Lee, Tae Won Noh
Enhanced Flexoelectricity At Reduced Dimensions Revealed By Mechanically Tunable Quantum Tunnelling, Saikat Das, Bo Wang, Tula R. Paudel, Sung Min Park, Evgeny Y. Tsymbal, Long-Qing Chen, Daesu Lee, Tae Won Noh
Evgeny Tsymbal Publications
Flexoelectricity is a universal electromechanical coupling effect whereby all dielectric materials polarise in response to strain gradients. In particular, nanoscale flexoelectricity promises exotic phenomena and functions, but reliable characterisation methods are required to unlock its potential. Here, we report anomalous mechanical control of quantum tunnelling that allows for characterising nanoscale flexoelectricity. By applying strain gradients with an atomic force microscope tip, we systematically polarise an ultrathin film of otherwise nonpolar SrTiO3, and simultaneously measure tunnel current across it. The measured tunnel current exhibits critical behaviour as a function of strain gradients, which manifests large modification of tunnel barrier …