Colloquium on June 25, 2012

Hari C. Manoharan

Department of Physics, Stanford University

Molecular Graphene

The observation of massless Dirac fermions in monolayer graphene has propelled a new area of science and technology seeking to harness charge carriers that behave relativistically within solid-state materials.  Using low-temperature scanning tunneling microscopy and spectroscopy, we show the emergence of Dirac fermions in a fully tunable condensed-matter system—molecular graphene—assembled via atomic manipulation of a conventional two-dimensional electron system.  Into these electrons we embed, map, and tune the symmetries underlying the two-dimensional Dirac equation.  With altered symmetry and texturing, these Dirac particles can be given a tunable mass, or even dressed with fictitious electric or magnetic fields (so-called gauge fields) such that the carriers believe they are in real fields and condense into the corresponding ground state.  This talk will describe how molecular graphene seeds a versatile path, via tailored nanostructures, to synthesize unique devices and exotic topological phases in quantum materials [1].

[1] K. K. Gomes, W. Mar, W. Ko, F. Guinea, and H. C. Manoharan, “Designer Dirac Fermions and Topological Phases in Molecular Graphene,” Nature, 483, 306–310 (2012).