Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging nanoscale Fermi surface variations in an inhomogeneous
  superconductor   Particle-wave duality suggests we think of electrons as waves stretched
across a sample, with wavevector k proportional to their momentum. Their
arrangement in "k-space," and in particular the shape of the Fermi surface,
where the highest energy electrons of the system reside, determine many
material properties. Here we use a novel extension of Fourier transform
scanning tunneling microscopy to probe the Fermi surface of the strongly
inhomogeneous Bi-based cuprate superconductors. Surprisingly, we find that
rather than being globally defined, the Fermi surface changes on nanometer
length scales. Just as shifting tide lines expose variations of water height,
changing Fermi surfaces indicate strong local doping variations. This
discovery, unprecedented in any material, paves the way for an understanding of
other inhomogeneous characteristics of the cuprates, like the pseudogap
magnitude, and highlights a new approach to the study of nanoscale
inhomogeneity in general.

20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci