Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Charge density waves in graphite; towards the magnetic ultra-quantum
  limit   Graphite is a model system for the study of three-dimensional electrons and
holes in the magnetic quantum limit, in which the charges are confined to the
lowest Landau levels. We report magneto-transport measurements in pulsed
magnetic fields up to 60 T, which resolve the collapse of two density wave
states in two, electron and hole, Landau levels at 52.3 and 54.2 T
respectively. We report evidence for a commensurate density wave at 47.1 T in
the electron Landau level. The theoretical modelling of these results predicts
that the ultra-quantum limit is entered above 73.5 T. This state is an
insulator, and we discuss its correspondence to the "metallic" state reported
earlier. We propose that this (interaction-induced) insulating phase supports
surface states that carry no charge or spin within the planes, but does however
support charge transport out of plane.

17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an