Point defects in GaP single crystals investigated by mechanical damping

Abstract

GaP:S was measured in the temperature range 300 ... 600 K and at frequencies near 7 0 and 140 kHz, respectively. I n samples of different stoichiometry two peaks could be c' bserved: Peak A at 350 K and peak B at 450 K. Peak A is attributed to the relaxation of 1 loint defects near the surface, peak B is probably due to Ga vacancies.Die Abhangigkeit der mechanischen Diimpfung von schwefeldotierten LEC Gap-Kri-s1,allen wurde im Temperaturbereich 300 ... 600 K und bei Frequenzen von 70 bzw. 140 kHz gemessen. I n Proben unterschiedlicher Stochiometrie konnten zwei Maxima beobachtet \rwden: A bei 350 K und B bei 450 K. A wird der Relaxation von Punktfehlern in Ober-fISchenniihe zugeordnet, B geht wahrscheinlich auP Ga-Leerstellen zuruck. Several authors already dealt with the internal friction in GaP (BOYLE, SLADEK; KIRILLOV et al.; KLIMM, PAUFLER; M~TROCHIN et al.;PESIN et al.; VERNER et al. I 1977 VERNER et al. I , 1979. VERNER et al. reported on 3 peaks of damping a t 403, 593, and 683 K :-'or undoped n-Gap. They attributed them to divacancies. KLIMM and PAUFLER found 'jwo peaks in S-doped LEC GaP which were attributed to point defect relaxation.

Key Role of Defects in Thermoelectric Performance of TiMSn (M = Ni, Pd, and Pt) Half-Heusler Alloys

“…For the lattice parameter, a , our finding for TiNiSn deviates from an experiment value of a negligible 0.2%, , whereas TiPdSn and TiPtSn values are in accordance to those in refs and , respectively. Band gaps will be discussed in the next section.…”

“…The equilibrium Bulk modulus, B 0 , elastic constants, c 11 , c 12 , c 44 , Poisson ratio, ν, and Young's modulus, Y, are obtained with CRYSTAL by solving the third-order Birch−Murnaghan isothermal equation of state. 32 For the lattice parameter, a, our finding for TiNiSn deviates from an experiment value of a negligible 0.2%, 33,34 whereas TiPdSn and TiPtSn values are in accordance to those in refs 9 and 35, respectively. Band gaps will be discussed in the next section.…”

“…Bulk modulus, B 0 , elastic contants, c 11 , c 12 , c 44 , Young’s modulus, Y , in GPa and Poisson ratio, ν. Literature date ara reported when available. b Ref , (EXP). c Ref , (EXP). d Ref , (EXP). e Ref , (THEO). f Ref , (THEO). g Ref , (THEO). …”