Infrared Lattice Absorption of Silicon and Germanium

Abstract

The two-phonon absorption bands of silicon and germanium are calculated taking into account the second-order dipole moment up to second-nearest neighbours. The agreement between the calculated and measured bands shows that the shell model used in our calculations gives quite good phonon dispersion curves. The detailed analysis of the remaining deviations between measured and calculated frequencies indicates that in some points of the Brillouin zone the shell model should be corrected.Die Zweiphononen-Absorptionsbanden von Silizium und Germanium werden berechnet, wobei das Dipolmoment zweiter Ordnung bis zu zweitniichsten Nachbarn berucksichtigt wird. Die Vbereinstimmung zwischen den berechneten und gemessenen Banden zeigt, daB das fur die Rechnungen zugrunde gelegte Schalenmodell die Phononendispersionskurven recht gut wiedergibt. Die niihere Betrachtung der restlichen Abweichungen zwischen gemessenen und berechnetenFrequenzen ergibt, daD in einem gewissen Bereich der Brillouinzone das Schalenmodell besser angepaBt werden sollte.

Molecular Motion on Semiconductor Surface via Tip-enhanced Multiple Excitation

“…The vibrational energy of B-CO, obtained in our calculation, is at resonance with the Si-bulk phonon continuum, whereas that of T-CO is off the resonance [39]. Therefore, the vibrational energy of B-CO is strongly coupled to the bulk phonons, and decays very rapidly.…”

Two-phonon infrared spectra of Si and Ge: Calculating and assigning features

“…Several papers present critical-point analysis for twophonon features in Si and Ge: the works by Johnson, 37 Johnson and Loudon, 42 Balkanski and Nusimovici, 43 Fray et al, 39 Kress, et al, 44 and Ikezawa and Ishigame, 36 indicated by acronyms J, JL, BN, FJQW, KBW, and II in Tables II and III that are discussed below. Johnson's paper contains a fairly thorough review of aspects of critical-point analysis in earlier work.…”

Lattice Dynamics and Infrared Absorption of Cesium Halides

“…The functions F,,,(w), independent of potential parameters, are defined and calculated in a manner analogous to that of [19] ; they are determined by the crystal structure and the eigenvectors and eigenvalues of the harmonic model. K is a constant being built of the eigenvectors and the eigenfrequency of the dispersion phonon.…”