Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced ultrafast relaxation rate in the Weyl semimetal phase of
  $\mathbf{MoTe_2}$ measured by time-and angle-resolved photoelectron
  spectroscopy   $\mathrm{MoTe_2}$ has recently been shown to realize in its low-temperature
phase the type-II Weyl semimetal (WSM). We investigated by time- and angle-
resolved photoelectron spectroscopy (tr-ARPES) the possible influence of the
Weyl points in the electron dynamics above the Fermi level $\mathrm{E_F}$, by
comparing the ultrafast response of $\mathrm{MoTe_2}$ in the trivial and
topological phases. In the low-temperature WSM phase, we report an enhanced
relaxation rate of electrons optically excited to the conduction band, which we
interpret as a fingerprint of the local gap closure when Weyl points form. By
contrast, we find that the electron dynamics of the related compound
$\mathrm{WTe_2}$ is slower and temperature-independent, consistent with a
topologically trivial nature of this material. Our results shows that tr-ARPES
is sensitive to the small modifications of the unoccupied band structure
accompanying the structural and topological phase transition of
$\mathrm{MoTe_2}$.

27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess