Far-infrared study of impurity local modes in gallium-doped PbTe

Far-infrared study of impurity local modes in Ni-doped PbTe

“…A change of the electronic state of an impurity center leads to a change of a force constant between an impurity atom and a lattice, which leads to the changing of the local mode frequency. According to our results, and results for PbTe doped with III group of elements [5,6], we concluded that mode at about 190 cm −1 (which we seen for both samples) corresponds to Ni 3+ ; mode at about 130 cm −1 corresponds to Ni 2+ (narrow line) and mode at about 165 cm −1 to Ni 1+ . Registered mode frequencies are between the characteristic Ga and In frequencies [5,6,15], but they do not satisfy the isotopic effect, which is consequence of the interaction between an impurity center and a lattice.…”

“…In our earlier papers [5,6], we analyzed the far-infrared reflection and Raman scattering spectra. We registered three local modes of impurities.…”

Far-Infrared Study of DX-Like Centers in Pb0.95Mn0.05Te(Ga)

“…[6]. At T = 300 K, the corresponding PbTe and MnTe-like vibration modes (TO/LO pairs) in Pb 1−x Mn x Te are (37/52) cm −1 and (54/107) cm −1 , respectively, as we obtained earlier [4]. Oscillator of a weak intensity, 70 cm −1 (the third term in Eq.…”

“…Oscillator of a weak intensity, 70 cm −1 (the third term in Eq. (1)), belong to modes from the edge of the Brillouin zone, where the density states of PbTe have maximum on these frequencies [4]. Beside the plasmon-phonon interaction, the broad structure appears for frequencies above ω + at T < 200 K. Taking into account the Raman measurements [5] and results from PbTe(Ga) [3] in Eq.…”

“…In our earlier papers we analyzed the Raman scattering and far-infrared reflection spectra of indium and gallium doped PbTe, pure Pb 1−x Mn x Te and indium doped Pb 1−x Mn x Te [3][4][5]. We found that the phonons in Pb 1−x Mn x Te show an intermediate one-two mode behavior.…”