title: New pathway for the formation of metallic cubic phase Ge-Sb-Te compounds induced by an electric current.
abstract: The novel discovery of a current-induced transition from insulator to metal in the crystalline phase of Ge2Sb2Te5 and GeSb4Te7 have been studied by means of a model using line-patterned samples. The resistivity of cubic phase Ge-Sb-Te compound was reduced by an electrical current (~1 MA/cm(2)), and the final resistivity was determined based on the stress current density, regardless of the initial resistivity and temperature, which indicates that the conductivity of Ge-Sb-Te compound can be modulated by an electrical current. The minimum resistivity of Ge-Sb-Te materials can be achieved at high kinetic rates by applying an electrical current, and the material properties change from insulating to metallic behavior without a phase transition. The current-induced metal transition is more effective in GeSb4Te7 than Ge2Sb2Te5, which depends on the intrinsic vacancy of materials. Electromigration, which is the migration of atoms induced by a momentum transfer from charge carriers, can easily promote the rearrangement of vacancies in the cubic phase of Ge-Sb-Te compound. This behavior differs significantly from thermal annealing, which accompanies a phase transition to the hexagonal phase. This result suggests a new pathway for modulating the electrical conductivity and material properties of chalcogenide materials by applying an electrical current.
authors.affiliation: Department of Materials Science &Engineering, Seoul National University, Seoul 151-744, Korea.
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Materials Science &Engineering, Seoul National University, Seoul 151-744, Korea.
authors.forename: Ju-Young
authors.initials: JY
authors.lastname: Cho
authors.affiliation: Department of Materials Science &Engineering, Seoul National University, Seoul 151-744, Korea.
authors.forename: Min-Woo
authors.initials: MW
authors.lastname: Jeong
authors.affiliation: Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Sekwon
authors.initials: S
authors.lastname: Na
authors.affiliation: Department of Materials Science &Engineering, Seoul National University, Seoul 151-744, Korea.|Research Institute of Advanced Materials (RIAM), Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Young-Chang
authors.initials: YC
authors.lastname: Joo