First principles study of crystal Si-doped Ge2Sb2Te5. (February 2017)

• Record Type: Journal Article
• Authors: Yan, Beibei; Yang, Fei; Chen, Tian; Wang, Minglei; Chang, Hong; Ke, Daoming; Dai, Yuehua
• Is Part Of: Solid state communications. Volume 252(2017)
• Page Start: 6
• Page End: 10
• Publication Date: 2017-02
• Subjects: GST -- First-principles -- Si-doping -- Doping concentration; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2017.01.001
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: Ge2 Sb2 Te5 (GST) and Si-doped GST with hexagonal structure were investigated by means of First-principles calcucations. We performed many kinds of doping types and studied the electronic properties of Si-doped GST with various Si concentrations. The theoretical calculations show that the lowest formation energy appeared when Si atoms substitute the Sb atoms (SiSb ). With the increasing of Si concentrations from 10% to 30%, the impurity states arise around the Fermi level and the band gap of the SiSb structure broadens. Meanwhile, the doping supercell has the most favorable structure when the doping concentration keeps in 20%. The Si-doped GST exhibits p-type metallic characteristics more distinctly owing to the Fermi level moves toward the valence band. The Te p, d‐orbitals electrons have greater impact on electronic properties than that of Te s-orbitals. Highlights: Ge2 Sb2 Te5 (GST) and Si-doped GSTwere investigated by First-principles calcucations based on density function theory. Different forms of doping and the Si-doped GST with various Si concentrations were studied. Structure of Si atom substitute the Sb atom (SiSb ) is most likely to form. The doping supercell has the most favorable structure when the doping concentration keeps in 20%. The location of the doping atoms has no effect to the DOS and the d orbital contribution is the most significant.