We investigate the isospin properties of the strange quark matter (SQM) and quark stars (QSs) in the framework of the isospin-dependent confining quark matter (ICQM) model and confined-isospin and density-dependent mass (CIDDM) model. Within these two isospin-dependent quark mass phenomenological models, we study the quark matter symmetry energy, the stability of strange quark matter, the quark fractions, the isospin asymmetry, and the quark mass asymmetry in SQM, and the mass-radius relation of quark stars. We find that including isospin depen...
