Most websites claiming to offer a free PDF of "Marder Condensed Matter Physics Solutions" are either:
Michael Marder’s Condensed Matter Physics is widely considered a modern, comprehensive alternative to the classic Ashcroft & Mermin text. While the official full solutions manual is technically restricted to instructors, several academic sources provide selected solutions. Review of Marder's Problems and Solutions marder condensed matter physics solutions pdf free
Because Marder is so dense, it is best tackled as a "team sport." Explaining a concept to a peer is often more effective than reading a solution manual. 4. Key Topics Covered in Marder Most websites claiming to offer a free PDF