Finding a single, official "Solution Manual" PDF can be tricky, as many publishers restrict these to verified instructors. However, students have several reliable paths:
Calculating lattice heat capacity using the Einstein and Debye models. 4. The Free Electron Gas and Energy Bands Solid State Physics Ibach Luth Solution Manual
by and Hans Lüth is a staple in physics curricula for its balance of theoretical rigor and experimental reality. Report: Solid State Physics by Ibach & Luth