Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Role of nematicity in controlling spin fluctuations and superconducting
  Tc in bulk FeSe   FeSe undergoes a transition from a tetragonal to a slightly orthorhombic
phase at 90\,K, and becomes a superconductor below 8\,K. The orthorhombic phase
is sometimes called a nematic phase because quantum oscillation, neutron, and
other measurements detect a significant asymmetry in $x$ and $y$. How
nematicity affects superconductivity has recently become a matter of intense
speculation. Here we employ an advanced \emph{ab-initio} Green's function
description of superconductivity and show that bulk tetragonal FeSe would, in
principle, superconduct with almost the same T$_{c}$ as the nematic phase. The
mechanism driving the observed nematicity is not yet understood. Since the
present theory underestimates nematicity, we simulate the full nematic
asymmetry by artificially enhancing the orthorhombic distortion. For
benchmarking, we compare theoretical spin susceptibilities against
experimentally observed data over all energies and relevant momenta. When the
orthorhombic distortion is adjusted to correlate with observed nematicity in
spin susceptibility, the enhanced nematicity causes spectral weight
redistribution in the Fe-3d$_{xz}$ and d$_{yz}$ orbitals, but it leads to at
most 10-15$\%$ increment in T$_{c}$. This is because the d$_{xy}$ orbital
always remains the most strongly correlated and provides most of the source of
the superconducting glue. Nematicity suppresses the density of states at Fermi
level; nevertheless T$_{c}$ increases, in contradiction to both BCS and BEC
theories. We show how the increase is connected to the structure of the
particle-particle vertex. Our results suggest while nematicity may be intrinsic
property of bulk FeSe, is not the primary force driving the superconducting
pairing.

32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an