Study of Lattice Instability by mm‐Wave Magnetoplasma Reflection in PbTeSnTe Compound Semiconductors

Abstract

The static dielectric constant cg in Pbl-,Sn,Te (z = 0 to 0.4) single crystals is dctcrmined from a magnetoplasma reflection measurement between 4.2 and 100 K. At high temperat>ures E* increases with increasing temperature obeying a Curie law. The Cwie constant is practically unchanged for different alloy composition, and the inverse static dielectric constant a t 4.2 K decreases lineaarly with z, going to zero at alloy composition z = 0.35. At z = 0.40, a phase transition is observed at 20 K. The temperatnre dependence of cS is explained by anharmonic terms of lattice vibrations. La constant dielectrique cS dans les monocristals P b l -,Sn,Te (z = 0 to 0,4)-a 6tB determine par la mesure de reflexion de magneto-plasma B tempkratures entre 4.2 e t 100 K. A hautes tempkratures, cS augmente avec temperature par la loi de Curie. Les constantes de Curie dans alliage compositions differentes ne different pas de I'un l'autre, e t l/cS A 4.2 K diminuent en ligne directe avec z et vont A zero B alliage composition x = @,35. A z = 0,40; la transition de phase est trouve B 20 K. La dkpendance de temperature de eS est expliqui. par le terme de anharmonique de vibration de r6seau.

Quantum Paraelectric States in SrTiO3and KTaO3: Barrett Model, Vendik Model, and Quantum Criticality

“…4) He derived an equation to compute the square of the soft-mode frequencyω 2 (T ). This equation was later derived in a different but more general manner as 5)…”

Low-temperature nonlinear microwave response of incipient ferroelectrics

“…At lower temperatures as a result of freezing of dipoles, the dispersion region shifted to low frequencies. In Reference 25 were studied dielectric permittivity and losses of (K, Li)Ta03 crystals in the frequency range [25][26][27][28][29][30][31][32][33][34][35][36][37] GHz at temperatures 4.2-100 K, in conditions where dielectric response was free of dipole relaxation and was caused by soft mode polarization of bulk lattice. Low-temperature dependences of dielectric permittivity of crystals with different lithium atoms concentration are shown in Figure 3a.…”

Mid-infrared photoconductive properties of heavily Bi-doped PbTe p–n homojunction diode grown by liquid-phase epitaxy

“…The photocurrent density of the heavily Bi-doped sample is approximately 20 times and 3 times greater than that of the undoped sample and heavily In-doped sample, respectively. Since PbTe systems are characterized by a high electric constant (e = 1400-1800) [11], we previously assumed that the high Bi concentration induced strong self-compensation, reducing the number of free electrons and the wide depletion layer [4,5]. Moreover, the free electrons in the n-type layer absorb less infrared radiation in heavily Bi-doped materials than in the other evaluated materials.…”