دراسة تحليلية للسعة الحرارية المولية عند ثبوت الحجم لمادة كبريتيد القصدير باستخدام نموذج ديباي

Abstract

Tin sulfide (SnS) is an important IV-VI semiconductor material with promising applications in thermoelectric materials and solar cells. The objective of this study is to determine the molar heat capacity at constant volume C_v for tin sulfide SnS. This was theoretically investigated using the Debye model, employing the Debye approximation to describe the contribution of lattice vibrations to the heat capacity across a wide range of temperatures. A Debye temperature of 218 K was adopted for this material. Theoretical calculations were performed using MATLAB simulation. The calculated results showed the expected behavior of the molar heat capacity C_v, which is proportional to the cube of the absolute temperature T³ at low temperatures and approaches the classical Dulong-Petit limit at high temperatures. The theoretical C_v results were compared with available experimental results for heat capacity at constant pressure (C_p). The obtained results showed good agreement with published experimental data in the scientific literature, with a relative deviation of approximately 0.34% at 250 K. However, an increasing deviation was observed at low temperatures 13.00% at 100 K and high temperatures 6.50% at 600 K. This indicates that the Debye model provides an excellent approximation in the intermediate range, and the deviations are attributed to a harmonic effect as well as the difference between C_v and C_p. This study provides a reliable analytical framework for estimating the thermal properties of SnS.