Atomic-scale Views of Complex Materials
Abhay Pasupathy, Columbia University
I
will describe recent scanning tunneling microscopy (STM) research in my
laboratory at Columbia University. We are currently looking at two
low-dimensional materials, the transition-metal dichalcogenides (TMD)
and large-area monolayer graphene-based films. On the TMD materials,
our
aim is to visualize the charge density wave (CDW) phase transition in
real space as a function of temperature. We have performed such
experiments on NbSe2 which reveal a surprisingly new picture for how
CDW order develops in these materials. On graphene, our interest is to
image
and perform spectroscopic measurements of large-area films of graphene
that are grown by chemical vapor deposition (CVD). I will describe
experiments where we can grow graphene by CVD on single crystal
substrates, as well as experiments where these large-area films are
substitutionally doped using nitrogen atoms.