Superconductivity, hole concentration and peritectic transition of La1.5CaxBa1.5−xCu3Oy compounds

In this work, Bi0.5Sb1.5Te3 materials were produced by an economically viable and time efficient water atomization process. The powder samples were heat treated at different temperatures (673 K, 723 K, 743 K, 773 K, 803 K, and 823 K) followed by spark plasma sintering (SPS). It was found that the Te evaporated slightly at 723 K and 743 K and became dominated at 773 K, 803 K, and 823 K, which severely influences the thermoelectric properties. The electrical conductivity was significantly improved for over 803 K heat treated samples due to the remarkable improvement in hole concentration. The power factor values for the 803 K and 823 K samples were significantly larger at T > 350 K compared to other samples. Consequently, the peak ZT of 0.92 at 350 K was obtained for the 803 K sample, which could be useful in commercial thermoelectric power generation.

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Bond equilibrium theory for Te-rich liquid Tl–Te alloys

Canadian Journal of Chemistry ◽

10.1139/v77-269 ◽

1977 ◽

Vol 55 (11) ◽

pp. 1930-1936 ◽

Cited By ~ 2

Author(s):

Melvin Cutler

Keyword(s):

Free Energy ◽

Good Description ◽

Hole Concentration ◽

Enthalpy Of Mixing ◽

Dangling Bond ◽

Fermi Model ◽

Bond Model ◽

Independent Information ◽

Molecular Bond ◽

Rich Liquid

Recent work has provided independent information about the behavior of the hole concentration c in TlxTe1−x as a function of temperature T and composition x in the range 0.2 ≤ x ≤ 0.6. This makes possible a critical reexamination of a molecular bond model for the structure of the alloy, in which holes are generated by broken Te—Te bonds. The earlier theory is revised to formulate an unrestricted independent bond model (ibm), for which the equations are simple and have obvious physical interpretations. This provides a good description of c(T) but only a qualitatively correct c(x). Using a Thomas–Fermi model for the screening interaction between holes and the acceptor ions, it is shown that the equilibrium constant can be expected to increase rapidly with c at large enough values. A modification in which the free energy of a dangling bond is decreased by proximity to a Tl—Te bond is found to significantly improve the result for c(x). The thermochemical behavior is derived. The entropy of mixing is in fair agreement with experiment, but the enthalpy of mixing is grossly wrong. This reflects the neglect of intermolecular interactions in the theory, which, it seems, can easily account for the remaining discrepancies in the predicted behavior of c.

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Effects of Ce filling fraction and Fe content on the thermoelectric properties of Co-rich CeyFexCo4−xSb12

Journal of Materials Research ◽

10.1557/jmr.2001.0109 ◽

2001 ◽

Vol 16 (3) ◽

pp. 837-843 ◽

Cited By ~ 66

Author(s):

Xinfeng Tang ◽

Lidong Chen ◽

Takashi Goto ◽

Toshio Hirai

Keyword(s):

Thermal Conductivity ◽

Thermoelectric Properties ◽

Figure Of Merit ◽

Single Phase ◽

Lattice Thermal Conductivity ◽

Hole Concentration ◽

Thermoelectric Figure Of Merit ◽

Thermoelectric Figure ◽

Filling Fraction ◽

Fe Content

Single-phase filled skutterudite compounds, CeyFexCo4−xSb12 (x = 0 to 3.0, y = 0 to 0.74), were synthesized by a melting method. The effects of Fe content and Ce filling fraction on the thermoelectric properties of CeyFexCo4−xSb12 were investigated. The lattice thermal conductivity of Ce-saturated CeyFexCo4−xSb12, y being at the maximum corresponding to x, decreased with increasing Fe content (x) and reached its minimum at about x = 1.5. When x was 1.5, lattice thermal conductivity decreased with increasing Ce filling fraction till y = 0.3 and then began to increase after reaching the minimum at y = 0.3. Hole concentration and electrical conductivity of Cey Fe1.5Co2.5Sb12 decreased with increasing Ce filling fraction. The Seebeck coefficient increased with increasing Ce filling fraction. The greatest dimensionless thermoelectric figure of merit T value of 1.1 was obtained at 750 K for the composition of Ce0.28Fe1.52Co2.48Sb12.

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The Effects of Amorphous Layer Regrowth on Carbon Activation in GaAs and InP

MRS Proceedings ◽

10.1557/proc-316-325 ◽

1993 ◽

Vol 316 ◽

Author(s):

A.J. Moll ◽

J.W. Ager ◽

K.M. Yu ◽

W. Walukiewicz ◽

E.E. Haller

Keyword(s):

Hole Concentration ◽

Amorphous Layer ◽

Free Hole ◽

Initial Results

ABSTRACTThe effect of the Ga dose on the activation of implanted carbon in GaAs is determined. The free hole concentration is found to depend on the depth of the amorphous layer created by the Ga co-implant. Initial results on C implantation in InP indicate the behavior of C is very different in InP when compared to GaAs. The role of precipitation in reducing the activation of C in both GaAs and InP is discussed.

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Phase-field investigation on the peritectic transition in Fe-C system

Acta Materialia ◽

10.1016/j.actamat.2021.117223 ◽

2021 ◽

pp. 117223

Author(s):

Yuhan Cai ◽

Fei Wang ◽

Zihan Zhang ◽

Britta Nestler

Keyword(s):

Phase Field ◽

Field Investigation ◽

Peritectic Transition

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An effective and efficient approach to p-type AlN by Be2:O codoping from first-principles calculations

Modern Physics Letters B ◽

10.1142/s0217984916502572 ◽

2016 ◽

Vol 30 (20) ◽

pp. 1650257

Author(s):

Meng Zhao ◽

Wenjun Wang ◽

Jun Wang ◽

Junwei Yang ◽

Weijie Hu ◽

...

Keyword(s):

First Principles ◽

Ionization Energy ◽

Hole Concentration ◽

Valence Band Maximum ◽

First Principles Calculations ◽

Mutual Compensation ◽

Efficient Approach ◽

P Type ◽

Codoping Method

Various Be:O-codoped AlN crystals have been investigated via first-principles calculations to evaluate the role of the different combinations in effectively and efficiently inducing p-type carriers. It is found that the O atom is favored to bond with two Be atoms. The formed Be2:O complexes decrease the acceptor ionization energy to 0.11 eV, which is 0.16 eV lower than that of an isolated Be in AlN, implying that the hole concentration could probably be increased by 2–3 orders of magnitude. The electronic structure of Be2:O-codoped AlN shows that the lower ionization energy can be attributed to the interaction between Be and O. The Be–O complexes, despite failing to induce p-type carriers for the mutual compensation of Be and O, introduce new occupied states on the valence-band maximum (VBM) and hence the energy needed for the transition of electrons to the acceptor level is reduced. Thus, the Be2:O codoping method is expected to be an effective and efficient approach to realizing p-type AlN.

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