Lattice dynamic properties of BaSi2 and BaGe2 from first principle calculations

Mechanical, electronic and thermodynamic properties of C14-type AMg2 (A=Ca, Sr and Ba) compounds from first principles calculations

“…This can be attributed to the difference of lattice constants which leads to the difference of bond lengths. It is known that a shorter bond length leads to larger force constants, resulting in higher vibrational frequencies [56]. This phenomenon is similar to the C15-type Al 2 Ca and Al 2 Mg compounds studied by Deligoz et al [53].…”

Detection of local vibrational modes induced by intrinsic defects in undoped BaSi2 light absorber layers using Raman spectroscopy

“…Table I shows 34,36,37 and by calculation. 35 Terai et al also pointed out such a feature of modes in the measurement of the angle dependencies of polarized Raman spectra of a-axis-oriented undoped BaSi 2 epitaxial films on Si(001). 37 Comparing the present calculated peak positions of Raman active modes to the experimental result in powdered BaSi 2 , 34 we confirm that the peak positions are almost reproducible.…”

“…32,33 However, there has been no such discussion about defects in BaSi 2 although there have been several reports on Raman spectra of BaSi 2 from both experimental and theoretical viewpoints so far. [34][35][36][37] In this work, we first estimate residual stresses in the a-axis-oriented BaSi 2 epitaxial films grown on a Si(111) substrate based on the lattice constants deduced from x-ray diffraction measurements. This is to qualitatively understand the shift of the Raman peak position and discuss their origins.…”

“…As the lattice constants of the relaxed sample, those of powdered XRD are used 50. Following Hooke's law, the residual stress in the film is obtained from the evaluated strain as where s ijkl are the compliance constants of single crystal BaSi 2 , and the values calculated by Peng et al are used for them 35. Evaluation of the residual stress in the film by XRD is carried out assuming an in-plane stress condition (r 11 ¼ r 12 ¼ r 13 ¼ 0) as applied to, for example, h111i-oriented Al thin films on a Si(001) substrate 51.…”

“…34-37. They are based on the results of powdered BaSi 2 ,34 phonon density of states (DOS),35 BaSi 2 film on Si(001) by vacuum evaporation,36 and BaSi 2 film on Si(001) by MBE 37. Schematics of Raman active A g modes calculated at the C point in a BaSi 2 perfect crystal at (a) 499.8 cm À1 and (b) 502.5 cm À1 .TABLE III.…”