Reconstructions and stabilities of PbTe(111) crystal surface from experiments and density-functional theory

• Published in: Applied surface science Vol. 356; pp. 742 - 746
• Main Authors: Wu, Haifei, Si, Jianxiao, Yan, Yonghong, Liao, Qing, Lu, Yunhao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.11.2015
• Subjects: Crystal surfaces; Epitaxial growth; First principal calculations; Lead (metal); Mathematical analysis; Reconstruction; Reflection; Reflection high energy electron diffraction; Surface properties; Surface reconstruction; Thin films; Reflection high energy electron diffraction; Surface reconstruction; First principal calculations
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.08.126

•PbTe(111) surface studied by the combined experimental/theoretical approach.•PbTe surface structure can be manipulated by control the experimental conditions.•Metastable (1×1) structure is formed on the PbTe(111) surface at Tsub=250°C.•Stable (2×1) reconstructions appear on the PbTe(111) surface at Tsub≥300°C. Surface properties of epitaxially grown PbTe(111) thin films on BaF2(111) substrates were systematically investigated by the characterizations of in situ reflection high energy electron diffraction (RHEED) and atomic force microscope (AFM). First principal calculations were performed to facilitate the interpretation of experimental observations. Our results indicate that substrate temperature (Tsub) and chemical environment are crucial in determining the type of surface structure during the growth of PbTe(111) thin films. When PbTe is grown at Tsub=250°C, the metastable (1×1) structure is formed on the PbTe(111) surface. However, whether Tsub is elevated to 300°C or the PbTe(111)-(1×1) sample grown at Tsub=250°C is post-annealed at 300°C, the stable (2×1) reconstructions appear on the PbTe(111) surface. In Pb-rich environment, the most stable (2×1) reconstruction results from the substitution of the half of the 2nd Te atoms by Pb atoms, while in Te-rich environment, the most stable (2×1) reconstruction originates from the missing of half of the 1st Pb atoms.