Phase transitions in single crystal tubes formed from C60 molecules under high pressure

Pure single crystal tubes formed from C60 molecules, with a face-centered cubic (fcc) structure were fabricated by a liquid–liquid interfacial precipitation method using C60 powder. A bulk transition from fcc to a simple cubic structure and a surface transition from (1 × 1) to (2 × 2) have been observed around 246 K (bulk transition temperature TB) and 214 K (surface transition temperature TS), respectively, during the measurement of the temperature dependence of electrical resistance. The initiation of the two transitions under pressure was investigated using a piston cylinder high pressure apparatus and it was found that both TB and TS increase with increasing pressure. And the C60 molecules at the surface of the tube exhibit the same behavior of that in the bulk at a pressure of about 2.1 GPa.