  We propose a new model of flavour chiral symmetry breaking in a
(2+1)-dimensional defect gauge theory of strongly coupled fermions by
introducing probe D5/anti-D5-flavour branes on the conifold. After working out
the flavour brane embeddings at zero temperature, we thoroughly investigate the
spectra of small fluctuations on the world volume of the flavour branes (meson
spectrum) and conclude that they are free of tachyons. Thus the proposed probe
brane embedding is stable. Moreover, we introduce finite temperature and an
external magnetic field and study the thermodynamics of the resulting
configurations. Namely, we compute the free energies, entropies, heat
capacities and magnetisations. The results are used to establish a detailed
phase diagram of the model. We find that the effect of magnetic catalysis of
chiral symmetry breaking is realised in our model and show that the
meson-melting phase transition coincides with the chiral symmetry breaking
phase transition. Furthermore, we show that the model is in a diamagnetic
phase.
