Crystal Structures and Thermoelectric Properties of Ru1-xRexSiy Chimney-Ladder Compounds

2006 ◽  
Vol 980 ◽  
Author(s):  
Akira Ishida ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structures ◽  
Thermoelectric Properties ◽  
Valence Electron ◽  
Phase Relationship ◽  
Counting Rule ◽  
Electron Counting ◽  
Wide Compositional Range ◽  
P Type ◽  
Relationship Of ◽  
Semiconducting Behavior

AbstractThe phase relationship of Re-alloyed Ru2Si3 and the variations of the crystal structures and thermoelectric properties of the Ru1-xRexSiy chimney-ladder phases have been studied as a function of the Re concentration. The Ru1-xRexSiy chimney-ladder phases are formed in a wide compositional range. Compositional formula of the chimney-ladder phases are determined to be Ru1-xRexSi1.5386+0.1783x (0.14 ≤ x ≤ 0.76), which are systematically deviated from the idealized composition conforming the valence electron counting rule: VEC=14. Measurements of thermoelectric properties of single crystals with different compositions reveals that the chimney-ladder phases exhibit n-type semiconducting behavior at low Re concentrations and p-type semiconducting behavior at high Re concentrations. These results suggests that the VEC=14 rule can be used for predicting the semiconducting behavior of the chimney-ladder phases through the adjustment of VEC values by substituting elements, producing p-type semiconductors for VEC<14 and n-type for VEC>14, with the carrier concentration related to the deviation from VEC=14.

Thermoelectric Properties of Ru2Si3-Based Chimney-Ladder Phases

2007 ◽  
Vol 561-565 ◽  
pp. 463-466 ◽  
Author(s):  
Kyosuke Kishida ◽  
Akira Ishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structures ◽  
Thermoelectric Properties ◽  
Electron Concentration ◽  
Valence Electron ◽  
Valence Electron Concentration ◽  
Compositional Range ◽  
Wide Compositional Range ◽  
P Type ◽  
Semiconducting Behavior

The variations of the crystal structures and thermoelectric properties of the Ru1-xRexSiy chimney-ladder phases were studied as a function of the Re concentration. A series of chimney-ladder phases with a compositional formula of Ru1-xRexSi1.539+0.178x are formed in a wide compositional range, 0.14 ≤ x ≤ 0.76. The composition of the chimney-ladder phase is systematically deviated from the idealized composition satisfying the valence electron concentration rule: VEC=14. Measurements of thermoelectric properties reveal that the chimney-ladder phases exhibit n-type semiconducting behavior at low Re concentrations and p-type semiconducting behavior at high Re concentrations, which are well consistent with the prediction based on the deviation of the composition of the chimney-ladder phase from the idealized composition.

Ferromagnetic Dirac Half-Metallicity in Transition Metal Embedded Honeycomb Borophene

2021 ◽  
Author(s):  
Yanxia Wang ◽  
Xue Jiang ◽  
Yi Wang ◽  
Jijun Zhao
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Valence Electron ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Next Generation ◽  
Half Metallicity ◽  
Counting Rule ◽  
Spintronic Devices ◽  
Electron Counting

Exploring two-dimensional (2D) ferromagnetic materials with intrinsic Dirac half-metallicity is crucial for the development of next-generation spintronic devices. Based on first-principles calculations, here we propose a simple valence electron-counting rule...

Defect Control and Defect Engineering of Transition-metal Silicides

2006 ◽  
Vol 980 ◽  
Author(s):  
Haruyuki Inui ◽  
Katsushi Tanaka ◽  
Kyosuke Kishida
Keyword(s):  
Transition Metal ◽  
Thermoelectric Properties ◽  
Valence Electron ◽  
Vacancy Concentration ◽  
Relative Magnitude ◽  
Defect Engineering ◽  
Counting Rule ◽  
Substitutional Element ◽  
Metal Silicides ◽  
Defect Control

AbstractThe microstructure, defect structure and thermoelectric properties of two different semiconducting transition-metal silicides, ReSi1.75 and Ru2Si3 upon alloying with a substitutional element with a valence electron number different from that of the constituent metal have been investigated in order to see if the crystal and defect structures of these silicides and thereby their physical properties can be controlled through defect engineering according to the valence electron counting rule. The Si vacancy concentration and its arrangement can be successfully controlled in ReSi1.75 while the relative magnitude of the metal and silicon subcell dimensions in the chimney-ladder structures can be successfully controlled in Ru2Si3. As a result, the improvement in the thermoelectric properties and the p- to n-type conduction transition are successfully achieved respectively for these semiconducting transition-metal silicides.

Effect of Cobalt-Substitution on the Structure and Thermoelectric Properties of Chimney-Ladder Solid Solution (Mn1-xCox)Siγ (γ~ 1.7)

2010 ◽  
Vol 74 ◽  
pp. 22-25 ◽  
Author(s):  
Yuzuru Miyazaki ◽  
Yoshitsugu Saito ◽  
Kei Hayashi ◽  
Kunio Yubuta ◽  
Tsuyoshi Kajitani
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Thermoelectric Properties ◽  
Valence Electron ◽  
Annealing Process ◽  
Axis Ratio ◽  
Cobalt Substitution ◽  
Valence Electrons ◽  
Unknown Factor ◽  
P Type

A partially cobalt-substituted solid solution of Nowotny chimney-ladder phase, (Mn1-xCox)Si􀀂, has been prepared using a tetra-arc-type furnace and a subsequent annealing process. The compounds consist of two tetragonal subsystems of [Mn1-xCox] and [Si], with an irrational c-axis ratio 􀀂 = cMn/cSi ~ 1.7. The crystal structure and thermoelectric properties of (Mn1-xCox)Si􀀂 solid solution were compared with those of the Fe-substituted solid solution, (Mn1-xFex)Si􀀂. In the case of Co-series, extra valence electrons are introduced relative to Fe-series, since the valence electron count is 3d74s2 for Co but 3d64s2 for Fe, respectively. It was naturally expected that the Feand Co-substituted MnSi􀀁 becomes n-type conductor from the p-type one at x > 0.23(5) and x > 0.06(1), respectively. Experimentally, the Fe-substituted samples become n-type at x > 0.28 but it is not the case for the Co-substituted ones. It is thus evident that there is an unknown factor which controls the thermoelectric properties of Co-substituted samples.

Thermoelectric Properties of Undoped CoSb3

2004 ◽  
Vol 449-452 ◽  
pp. 917-920 ◽  
Author(s):  
Il Ho Kim ◽  
G.S. Choi ◽  
M.G. Han ◽  
Ji Soon Kim ◽  
Jung Il Lee ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Transitions ◽  
Thermoelectric Properties ◽  
Single Phase ◽  
Arc Melting ◽  
Annealing Effects ◽  
P Type ◽  
Type Conduction ◽  
Semiconducting Behavior

CoSb3 compounds were prepared by the arc melting and their thermoelectric properties were investigated at 300K-600K. Annealing effects were examined and they were correlated to phase transformation and homogenization. Undoped CoSb3 showed p-type conduction and intrinsic semiconducting behavior at all temperatures examined. Thermoelectric properties were changed with constituent phases because α-CoSb2, β-CoSb and Sb are metallic or semimetallic phases while δ-CoSb3 is semiconducting phase. Thermoelectric properties were remarkably improved by annealing in vacuum and they were closely related to phase transitions. Single phase δ-CoSb3 was successfully obtained by annealing at 400°C for 24hrs.

Enhancing thermoelectric properties of p-type CoSb3 skutterudite by Fe doping

2021 ◽  
Vol 127 ◽  
pp. 105721
Author(s):  
Suchitra Yadav ◽  
Sujeet Chaudhary ◽  
Dinesh K. Pandya
Keyword(s):  
Thermoelectric Properties ◽  
Fe Doping ◽  
P Type

scholarly journals Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

2021 ◽  
Author(s):  
Dong Han ◽  
Rahma Moalla ◽  
Ignasi Fina ◽  
Valentina M. Giordano ◽  
Marc d’Esperonnat ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermoelectric Properties ◽  
Epitaxial Strain ◽  
P Type
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