Phonons, Einstein and Debye models of specific heat.
Analysis of ionic, covalent, molecular, and metallic bonds. solid state physics r l singhal pdf
While a PDF is convenient for searching keywords, a physical copy is often better for the long, complex derivations found in this subject. It is published by Kedar Nath Ram Nath and is generally affordable. Conclusion Phonons, Einstein and Debye models of specific heat