First-principles study of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Si</mml:mi></mml:mrow><mml:mrow><mml:mn>34</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ge</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>clathrates: Direct wide-gap semiconductors in Si-Ge alloys

Moriguchi, Koji; Munetoh, Shinji; Shintani, Akira

doi:10.1103/physrevb.62.7138

Cited by 121 publications

(108 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is illustrated in Figure 4 [42], where a particularly sharp peak can be seen in the calculated density of states at the position of E F for Ba 8 Si 46 . It was noted in the original report [22,43] that a similar behavior may hold for Na 2 Ba 6 Si 46 .…”

Section: Rattler Atoms and Narrow Bandsmentioning

confidence: 81%

“…Similarly, the K-and Ba-filled analog was found to have T c = 3.2 K [23]. Advances in synthesis, in particular high-pressure methods, led to the preparation of Ba 8 Si 46 for which the alkali metals were replaced completely by Ba [24]. This composition achieves a superconducting T c = 8 K. Ba 8 Si 46 prepared with a slight deficit of Ba was found to have T c as high as 9.0 K [25], which is a high-water mark for superconducting transition temperatures among sp 3 -bonded clathrates.…”

Section: Superconductivity In Si 46 Clathratesmentioning

confidence: 99%

“…The silicon clathrates were first synthesized in 1965 [7], when type-I Na 8 Si 46 and type-II Na x Si 136 were prepared. A large number of related compositions have since been synthesized, including those with frameworks of Ge and Sn, and cage-filling atoms including Na, K, Rb, Sr, Ba, Te, Cl, Br, I, Eu, H 2 .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Superconductivity and Magnetism in Silicon and Germanium Clathrates

Ross

2009

Nanoscale Magnetic Materials and Applications

View full text Add to dashboard Cite

Clathrates are materials containing closed polyhedral cages stacked to form crystalline frameworks. With Si, Ge, and Sn atoms populating these frameworks, a wide variety of electronic and vibrational properties can be produced in these materials, by substitution upon framework sites or through incorporation of ions in cage-center positions. Commonly-formed structures include the type I, type II, and chiral clathrate types, whose properties will be described here. Ba 8 Si 46 with the type

show abstract

Section: Rattler Atoms and Narrow Bandsmentioning

confidence: 81%

Section: Superconductivity In Si 46 Clathratesmentioning

confidence: 99%

See 1 more Smart Citation

Superconductivity and Magnetism in Silicon and Germanium Clathrates

Ross

2009

Nanoscale Magnetic Materials and Applications

View full text Add to dashboard Cite

show abstract

“…Moriguchi et al (Moriguchi et al, 2000) and Wang et al (Wang et al, 2008) investigated the theoretical Si x Ge 1−x type II clathrate (see chapter 4). To minimize the homonuclear bonding Si-Si or Ge-Ge in pentagonal rings, non stoichiometric compounds (x=1/17,4/17,5/17,12/17,13/17,16/17) have been investigated.…”

Section: Clathratementioning

confidence: 99%

“…In the absence of angle-resolved photoemission data, the band structure of clathrates has been discussed on the basis of tight-binding and ab-initio density functional (Hohenberg and Kohn, 1964;Kohn, 1999) (DFT) calculations Moriguchi et al, 2000;Saito and Oshiyama, 1995;. In particular, DFT studies within the local density approximation (Kohn and Sham, 1965) (LDA) predict (Moriguchi et al, 2000a;) that the Si-34 phase displays a "nearly-direct" band gap which is ∼ 0.7 eV larger than the one of bulk Si-2 diamond.…”

Section: Silicon Clathratementioning

confidence: 99%

SiC Cage Like Based Materials

Mélinon¹

2011

Silicon Carbide - Materials, Processing and Applications in Electronic Devices

View full text Add to dashboard Cite

A Novel Technique for Controlling Anisotropic Ion Diffusion: Bulk Single‐Crystalline Metallic Silicon Clathrate

et al. 2022

View full text Add to dashboard Cite

Na‐free Si clathrates consisting only of Si cages are an allotrope of diamond‐structured Si. This material is promising for various device applications, such as next‐generation photovoltaics. The probable technique for synthesizing Na‐free Si clathrates is to extract Na+ from the Si cages of Na24Si136. Vacuum annealing is presently a well‐known conventional and effective approach for extracting Na. However, this study demonstrates that Na+ cannot be extracted from the surface of a single‐crystalline type‐II metallic Si clathrate (Na24Si136) in areas deeper than 150 µm. Therefore, a novel method is developed to control anisotropic ion diffusion: this is effective for various compounds with a large difference in the bonding strength between their constituent elements, such as Na24Si136 composed of covalent Si cages and weakly trapped Na+. By skillfully exploiting the difference in the chemical potentials as a driving force, Na+ is homogeneously extracted regardless of the size of the single crystal while maintaining high crystallinity. Additionally, the proposed point defect model is evaluated via density functional theory, and the migration of Na+ between the Si cages is explained. It is expected that the developed experimental and computational techniques would significantly advance material design for synthesizing thermodynamically metastable materials.

show abstract

First-principles study ofSi34−xGexclathrates: Direct wide-gap semiconductors in Si-Ge alloys

Cited by 121 publications

References 36 publications

Superconductivity and Magnetism in Silicon and Germanium Clathrates

Superconductivity and Magnetism in Silicon and Germanium Clathrates

SiC Cage Like Based Materials

A Novel Technique for Controlling Anisotropic Ion Diffusion: Bulk Single‐Crystalline Metallic Silicon Clathrate

Contact Info

Product

Resources

About