Low-temperature properties of glassy and crystalline states of n-butanol

We present low-temperature measurements of the specific heat and the thermal conductivity for the three solid phases of n-butanol, namely glass, crystal and “glacial” phases. Whereas crystal and glass ones are found to exhibit the expected thermal behavior for crystalline and non-crystalline solids, respectively (i.e. Debye theory for crystals, and universal low-temperature properties with a boson peak and a concomitant plateau in the thermal conductivity for glasses), the so-called “glacial phase” behaves as a very defective crystal, confirming earlier work that identifies it as a mixed phase of nanocrystallites and a disordered matrix. We have also measured longitudinal and transverse sound velocities at low temperatures for the glass phase. The elastic Debye coefficient and Debye temperature of the glass determined from these measurements are found to agree very well with the calorimetric ones obtained from a SPM analysis of the specific heat.