Extended modifications of electronic structures caused by defects: Scanning tunneling microscopy of graphite

Electronic effects from two well-defined defects are identified and measured using scanning tunneling microscopy on graphite. An atomic vacancy on the topmost (0001) plane caused a lowering of apparent z height in a 30 {}×{}30 {} area by {~}1.5 {}. A plane rotation relative to the third surface layer caused a Moir\'e pattern, with an attenuation along the c axis about 2.6 per monolayer. A ``supervacancy'' was imaged due to competition between the above two effects. An explanation based on changes in density of states near the Fermi level is proposed.