Atomic and electronic structure of Sr/Si(001)-(2 x 2)

2006-09-15
Cakmak, M.
Mete, E.
Ellialtıoğlu, Süleyman Şinasi
The adsorption of Sr on the Si(001) surface with the semiantiphase dimer (2 x 2) reconstruction is studied, based upon the ab initio pseudopotential calculations. It is calculated that the sermantiphase dimer (2 x 2) reconstruction (2 dimers per unit cell) is more favorable than the (2 x 1) phase (I dimer per unit cell) by an energy of about 0.24 eV/dimer. Considering the energetically more stable reconstruction, we have assumed four possible locations for 1/4 monolayer (ML) Sr adsorption on this surface: (i) bridge, (ii) cave, (iii) pedestal, and (iv) valley-bridge. We find that Sr adsorption on the valley-bridge site is energetically more favorable than all other cases studied here. Interestingly, one of the dimers becomes symmetric, but the other one is still asymmetric with the buckling angle reduced from 18 degrees to 14 degrees, when compared with the clean Si(001)-(2 x 2) surface. The calculated bond length between Sr and Si in the case of valley-bridge adsorption site is 3.05 angstrom, and in good agreement with other theoretical calculations. We also present and compare the electronic band structures for the clean and covered surfaces as well as the corresponding charge density plots.
SURFACE SCIENCE

Suggestions

Electronic and structural properties of armchair SWCNT/TiO2(110)-(1 x 2) system
Tayran, C.; ÇAKMAK, MELEK; Elliatioglu, S. (Elsevier BV, 2011-03-01)
We have presented structural and electronic properties of single-walled carbon nanotubes (CNTs) with armchair chirality on the reconstructed rutile TiO2(110)-(1 x 2) surface by means of ab initio calculations using density functional theory. For the TiO2 surface reconstruction, we have adopted an added-row model which was experimentally proposed in parallel to STM patterns and theoretically agreed by first principle calculations. In this work, we have studied, as examples, two CNTs with different sizes, (3,...
An ab initio study of 3-aminopropyltrimethoxysilane molecule on Si(111)-(root 3 x root 3) surface
Demirel, G.; Birlik, G.; Cakmak, M.; Caykara, T.; Ellialtıoğlu, Süleyman Şinasi (Elsevier BV, 2007-09-15)
The chemisorption and reaction of 3-aminopropyltrimethoxysilane (APTS) molecule on the Si(111)-(root 3 x root 3) surface are investigated by first principles density-functional calculations within the generalized gradient approximation. Before studying the chemisorption of APTS molecule on the surface, we have firstly put three-OH groups on the silicon surface, but considering six different locations for H and O atoms. Upon their relaxations, model 11, which is assumed to be crosswise for initial orientatio...
Atomic and electronic structure of group-IV adsorbates on the GaAs(001)-(1 x 2) surface
Usanmaz, D.; ÇAKMAK, MELEK; Ellialtıoğlu, Süleyman Şinasi (Elsevier BV, 2009-09-01)
Ab initio calculations, based on pseudopotentials and density functional theory, have been performed to investigate the atomic and electronic structure of the group-IV adsorbates (C, Si, Ge, Sn, and Pb) on the GaAs(001)-(1 x 2) surface considered in two different models: (i) non-segregated Ga-IV-capped structure and (ii) segregated structure in which the group-IV atoms occupying the second layer while the As atom floats to the surface. The non-segregated structure is energetically more favorable than the se...
Ion beam synthesized lummescent Si nanocrystals embedded in SO2 films and the role of damage on nucleation during annealing
Mayandi, J.; Finstad, T. G.; Foss, S.; Thogersen, A.; Serincan, U.; Turan, Raşit (Elsevier BV, 2007-08-05)
Si nanocrystals in thermal oxide films (similar to 250 nm) were fabricated by 100 keV Si ion implantation followed by high temperature annealing. Two different doses were compared after annealing at 1050 degrees C for 2 h. A sample implanted with a dose of 1 x 10(17) cm(-2) shows a broad photo luminescence peak centered around 880 nm after annealing. A dose of 5 x 10(16) cm(-2) yields a considerable blue shift of about 100 nm relative to the higher dose as well as a reduction in intensity. Transmission elec...
Syntheses and Characterization of Benzotriazole, Thienopyrroledione, and Benzodithiophene Containing Conjugated Random Terpolymers for Organic Solar Cells
Goksu, Kardelen; Hizalan, Gonul; Udum, Yasemin Arslan; Hacioglu, Serife Ozdemir; Cevher, Sevki Can; Akrema, Akrema; Toppare, Levent Kamil; Çırpan, Ali (The Electrochemical Society, 2019-11-20)
Two random terpolymers bearing alkoxy-benzodithiophene as an electron-rich unit and N-octylthieno[3,4,c]pyrrole-4,6-dione (TPD) as an electron deficient group with thiophene and selenophene pi bridges, were synthesized and characterized. Electrochemical, optical properties of the polymers were analyzed to get an insight on the effect of different p bridges. Photovoltaic performances of the polymers were investigated with a conventional device architecture. PBTS, PBTSe based polymer solar cells (PSCs) exhibi...
Citation Formats
M. Cakmak, E. Mete, and S. Ş. Ellialtıoğlu, “Atomic and electronic structure of Sr/Si(001)-(2 x 2),” SURFACE SCIENCE, pp. 3614–3618, 2006, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56750.