Flores, FernandoOrtega, JoséPérez, Rubén2004-12-142004-12-1420012001http://hdl.handle.net/2003/1900410.17877/DE290R-1732enThe American Physical SocietyPhysical Review Letters530Surface Soft Phonon and the × 3×3 Phase Transition in Sn/Ge(111) and Sn/Si(111)10.1103/PhysRevLett.86.4891article (journal)