  In this paper, we present the first measurement of a Gallium Arsenide crystal
working as low-temperature calorimeter for direct Dark Matter (DM) searches
within the DAREDEVIL (DARk-mattEr DEVIces for Low energy detection) project. In
the quest for direct dark matter detection, innovative approaches to lower the
detection thershold and explore the sub-GeV mass DM range, have gained high
relevance in the last decade. This study presents the pioneering use of Gallium
Arsenide (GaAs) as a low-temperature calorimeter for probing the dark
matter-electron interaction channel. Our experimental setup features a GaAs
crystal at ultralow temperature of 15 mK, coupled with a Neutron Transmutation
Doped (NTD) thermal sensor for precise energy estimation. This configuration is
the first step towards the detection of single electrons scattered by dark
matter particles within the GaAs crystal, to significantly improve the
sensitivity to low-mass dark matter candidates.
