The phase transition in solid solutions of the (Agx/2Ge1-xSbx/2)Te type

Baleva, M.; Plachkova, S. K.

doi:10.1088/0022-3719/16/4/022

Cited by 17 publications

(11 citation statements)

References 13 publications

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“…7. Plot of p / K , ( 0 ) and (7n*/m0)3/2 ( 0 ) dependences vs. composition (5) for the GeTe-rich solid solutions (GeTe)l-,(AgSbTe,), at 300 K '' 1 -06 rhombohedral phase is positive and increasing with increasing temperature (from 300 K to TJ. (ii) As has been found experimentally for GeTe [16] and investigated in solid solutions the effective mass of holes above 300 K increases.…”

Section: Discussionmentioning

confidence: 99%

“…These integrals are modified so as to take into account the influence of the non-parabolicity not only on the dispersion law and energy dependence of the density of states, but as well on the transition probability matrix element [ll]. The value of E , in these calculations is taken equal to the value of the optical energy gap at 300 K [5] with temperature coefficient dE,/dT = -4 x…”

Section: The Composition Dependence Of the Thermal Conductivity At 300 Kmentioning

confidence: 99%

“…The solubility region is narrowed with decreasing temperature (x 5 0.63 a t 809 K and x < 0.30 at 300 K) [4]. The phase transition (0;-(2,"") temperature (T,) and the rhombohedra1 distortion decrease with increasing AgSbTe, content and from = 700 K for GeTe drops to 300 K at x 2 : 2 : 0.23 [ 5 ] .…”

Section: Introductionmentioning

confidence: 99%

“…The appearance of the dependences a ( T ) and e ( T ) is determined from the predominant scattering mechanisms and the changes in the band-edge structure connected with the phase transition. As a result of changes in the band-edge structure with temperature for definite composition (x = constant) specific temperature dependences of the fundamental energy gap [14,15] and specific changes in the fundamental gap for determined temperatures (T = constant) with composition (2)[5] occur. Also changed is the number of equivalent valleys occupied by carriers from one in the C& The temperature dependence of the specific resistivity for polycrystalline samples of the system (GeTe)l-,(AgSbTe,),.…”

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confidence: 99%

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Thermoelectric figure of merit of the system (GeTe)1−x(AgSbTe2)x

Placheova¹

1984

Phys. Stat. Sol. (a)

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The thermoelectric properties of polycrystalline samples of GeTe-rich side solid solutions (GeTe)l -, .. (AgSbTe,), for the compositions z = 0.00, 0.10, 0.15, 0.20, and 0.29 are investigated. The temperature dependences of the Seebeck coefficient and the electrical resistivity and the dependences of the total thermal conductivity a t 300 K versus composition are measured. The temperature dependences of the total thermal conductivity and the thermoelectric figure of merit 2 are calculated. The composition with maximum value of 2 is determined as GeTe + 20 mol% AgSbTe,.The reasons for the maximum thermoelectric figure of merit for this composition and for the anomaly changes in the thermoelectric parameters and the sharp increase of 2 in the region of phase transitions (Oi-C&,)are discussed.Die thermoelektrischen Eigenschaften von polykristallinen Proben der Mischkristalle (GeTe)l -, * . (AgSbTe,), nahe der Verbindung GeTe mit den Zusammensetzungen z = 0,OO; 0,lO; 0,15; 0,20 und 0,29 werden untersucht. Die Temperaturabhangigkeiten der Thermospannung und des spezifischen elektrischen Widerstandes und die Abhiingigkeiten der thermischen Leitfiihigkeit bei 300 K von der Zusammensetzung werden gemessen. Die Temperaturabhingigkeiten der thermischen Leitfiihigkeit und des thermischen Wirkungsgrades 2 werden berechnet. Die Zusammensetzung mit dem Maximalwert von 2 wird bestimmt zu GeTe + 20 Molyo AgSbTe,. Die Ursachen fur den maximalen Wirkungsgrad bei dieser Zusammensetzung und fur das scharfe Anwachsen von 2 im Gebiet der Phesenumwandlung (Oi-Civ) fur alle Zusammensetzungen werden diskutiert.

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Section: Discussionmentioning

confidence: 99%

Section: The Composition Dependence Of the Thermal Conductivity At 300 Kmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Thermoelectric figure of merit of the system (GeTe)1−x(AgSbTe2)x

Placheova¹

1984

Phys. Stat. Sol. (a)

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“…This was established by investigation of crystal structure [5], optical transition [8], and transport phenomena [9] in the system (GeTe)l-,(AgSbTe,), (y = 0.50). These alloys retain the crystal band structures and the basic characteristics of GeTe and because of this they can be viewed as pseudo IV-VI compounds.…”

Section: Introductionmentioning

confidence: 99%

Transport Phenomena of Ferroelectric Solid Solutions (GeTe)_1−x((Ag₂Te)_1−y(Sb₂Te₃)_y)_x with y = 0.60, 0 ≦ x ≦ 1 at 300 K

Christakudis

Plachkova

Avilov

et al. 1985

Physica Status Solidi (b)

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The variation of the transport coefficients a t 300 K, Seebeck coefficient (a), specific resistivity or conductivity (e = l/u), Hall coefficient (RH), and thermal conductivity ( K ) with the composition (2) for solid solution (GeTe)l-,((Ag2Te)l-1/(Sb,Te,)y), with y = 0.60 is investigated. The Hall coefficient decreases, reaches a t x = 0.40 the minimal value and increases then up to x = 1, but the variation of the other transport coefficients are monotonous with composition: a and e increase but K decreases with composition. The results are interpreted qualitatively on the base of the band edge model of GeTe with splitting of the Land Z-valleys of the Brillouin zone (BZ) at the ferroelectric Oh-Civ phase transition and the complicated form of the surfaces of constant energy. HCCJIeaOBaHbI H3MeHeHIIFI KHHeTIIqeCKIIX K03@@HUHeHTOB : TePM03AC ( a ) , CIIeqH@HseCKOe COIIPOTIIBJIeHIle (@ = l/U), KO3@@IIUIIeHT XOJIJIa (RH) II TeIIJIOIIpOBOAHOCTb ( K ) OT COCTaBa QHeHT XOJIJIa YMeHblIIaeTCR, AOCTHraR IIpII X = 0,40 MHHHMaJIbHOe 3HaqeHLle, a IIOTOM Ha9IIHaeT PaCTH BIIJIOT A0 Z = 1. OCTaJIbHbIe HHHeTHqeCKHe K03@@HqHeHTbI MBHFIIOTCFI IIJIaBHO CO COCTBBOM: H e yBeJIII9HBaIOTCH, a K yMeHblIIaeTCFI. Pe3yJIbTaTbI O~~H C H R -IOTCFI KaqeCTBeHHO Ha OCHOBe 30HHOr0 MoAeJIa GeTe C p a a~~e n n~m~~~r n e s L II 3EECTPe-(x) TBepAbIX pacmopon (GeTe)l-,(Ag,Te)l-y(Sb,Te,)y)a; y = 0,60 n p~ 300 K . HoB@@H-M Y M~I M H ~O H~I BpmIoeHa n p~ C~~H~T O~J I~I E T I I Y~C K O M nepexoae Oh-Oiv H C J I O X H O~~ @op-~o i i H~O~H~~~~T I I~~C K H X nosepxHocTei3.

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