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Cover Picture: Ab‐initio calculations and structural studies of (SiTe) 2 (Sb 2 Te 3 ) n ( n : 1, 2, 4 and 6) phase‐change superlattice films (Phys. Status Solidi RRL 4/2014)
Author(s) -
Saito Y.,
Tominaga J.,
Fons P.,
Kolobov A. V.,
Nakano T.
Publication year - 2014
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201470520
Subject(s) - superlattice , ab initio , ab initio quantum chemistry methods , materials science , scanning tunneling microscope , condensed matter physics , sputter deposition , transmission electron microscopy , substrate (aquarium) , crystallography , molecular physics , sputtering , chemistry , thin film , physics , nanotechnology , optoelectronics , molecule , oceanography , organic chemistry , geology
As a new candidate of interfacial phase‐change memory (iPCM) materials, (SiTe) 2 (Sb 2 Te 3 ) n films were investigated theoretically and experimentally by Saito et al. (pp. 302–306 ). Ab‐initio first principles simulation revealed that the (SiTe) 2 (Sb 2 Te 3 ) n structures were energetically stable. Based on the simulation, the (SiTe) 2 (Sb 2 Te 3 ) 4 films were successfully fabricated on a Si substrate by RF‐magnetron sputtering. The X‐ray diffraction analysis and transmission electron microscopy indicated that the superlattice films exhibited a strong fiber texture along the 001 axis of Sb 2 Te 3 normal to the substrate surface. The superlattice composed of two SiTe layers and four Sb 2 Te 3 layers could be clearly identified by a high angle‐annular dark‐field scanning transmission electron microscope image, which was in good agreement with the simulated structure. It was found from simulations including spin–orbit coupling that the topological invariant of (SiTe) 2 (Sb 2 Te 3 ) 1 was 1, which means to be topologically nontrivial. It is concluded that the (SiTe) 2 (Sb 2 Te 3 ) n superlattice is a potential candidate for iPCM materials which will be a platform for spin manipulation using the specific Dirac semi‐metallic band structure.