  We consider liquid xenon dark matter detectors for searching a light scalar
particle produced in the solar core, specifically one that couples to
electrons. Through its interaction with the electrons, the scalar particle can
be produced in the Sun, mainly through Bremsstrahlung process, and subsequently
it is absorbed by liquid xenon atoms, leaving prompt scintillation light and
ionization events. Using the latest experimental results of XENON1T and Large
Underground Xenon, we place bounds on the coupling between electrons and a
light scalar as $g_{\phi ee} < 7 \times 10^{-15}$ from S1-only analysis, and as
$g_{\phi ee} < 2 \times 10^{-15}$ from S2-only analysis. These can be
interpreted as bounds on the mixing angle with the Higgs, $\sin \theta < 2
\times 10^{-9} \, \left(7 \times 10^{-10}\right)$, for the case of a relaxion
that couples to the electrons via this mixing. The bounds are a factor few
weaker than the strongest indirect bound inferred from stellar evolution
considerations.
