Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anisotropy of Dirac cones and van Hove singularity in an organic Dirac
  fermion system   We propose an experimental method to examine the in-plane anisotropy of
electronic structure in layered conductors. In the method, we measure the
interlayer magnetoresistance as a function of in-plane magnetic field
orientation. We applied it to an organic Dirac fermion system a-(BEDT-TTF)2I3
to experimentally determine the orientation of the anisotropic Dirac cones. It
is concluded that the long axis of the elliptic constant-energy contours of the
Dirac cone is tilted by approximately -30 deg from the crystalline a-axis to
b-axis under hydrostatic pressures. Additionally, we observed a signature of
van Hove singularity (which is a saddle point of the band dispersion) at 30-40
K above or below the Dirac point. The ridgeline of the saddle point is
estimated as almost parallel to the crystalline b-axis.

28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
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
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg