Local structure of NaCl-type crystalline Ge2 Sb2 Te5 has been studied by the atomic pair distribution function analysis of pulsed neutron powder diffraction data. We have found the large displacement of germanium atoms in this crystalline phase. Usually, such a large lattice distortion has disadvantages for the electric conductivity. The electronic band structure, however, implies that this significant distortion in addition to the lattice defect at Na site reduces only thermal conductivity, while the highly ordered tellurium atoms at Cl site keep high electric conductivity.
Bibliographical noteFunding Information:
The authors thank Professor T. Kajitani for his encouragement, E. Maxy, Dr. J. Nakamura, and K. Kawahara for their help, and Professor Y. Kameda for fruitful discussion. This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. This work has benefited from the use of NPDF at the Lujan Center at Los Alamos Neutron Science Center, Los Alamos National Laboratory and Argonne National Laboratory are funded by DOE under Contract No. W-7405-ENG-36 and W-31-109-ENG-38, respectively. The upgrade of NPDF has been funded by NSF through Grant No. DMR 00-76488.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)