Low Temperature Specific Heat of BiOX (X = Cl, Br, and I) Single Crystals

Low temperature specific heat of layered bismuth oxyhalide crystals has been studied in the temperature range from 2 to 50 K in zero and 8 T magnetic field The expected Debye-like behaviour at the lowest temperatures (below 4-5 K) is established Linear dependences of entropy and the Debye temperature as cross-correlation parameters are established The small values of the Debye temperature and peculiarities of phonon spectra at lowest temperatures are discussed