Röntgenstrukturanalysen an Einkristallen von Ce2S3 im A- und C-Typ

Schleid, Thomas; Lauxmann, Petra

doi:10.1002/(sici)1521-3749(199907)625:7<1053::aid-zaac1053>3.0.co;2-z

Cited by 18 publications

(14 citation statements)

References 6 publications

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“…Its primitive cell is composed of two coaxial helices with one formed by three Hg atoms and the other by three S atoms. The optimized lattice parameters are a ∼ 4.389Å, c ∼ 9.707Å (a ∼ 4.023Å, c ∼ 9.286Å) from the GGA (LDA) calculations, which are higher (lower) than the experimental values of a ∼ 4.15Å, c ∼ 9.50Å [42], and consistent with previous calculations with the same exchange-correlation functional [20].…”

Section: Resultssupporting

confidence: 87%

Low lattice thermal conductivity and good thermoelectric performance of cinnabar

Zhao

Dai

Lian

et al. 2017

Phys. Rev. Materials

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Based on the combination of first-principles calculations, Boltzmann transport equation, and electron-phonon interaction (EPI), we investigate the thermal and electronic transport properties of crystalline cinnabar (α-HgS). The calculated lattice thermal conductivity κ L is remarkably low, e.g., 0.60 Wm −1 K −1 at 300 K, which is about 30% of the value for the typical thermoelectric material PbTe. Via taking fully into account the k dependence of the electron relaxation time computed from the EPI matrix, the accurate numerical results of thermopower S, electrical conductivity σ , and electronic thermal conductivity κ E are obtained. The calculated power factor S 2 σ is relatively high while the value of κ E is negligible, which, together with the fairly low κ L , leads to a good thermoelectric performance in the n-type doped α-HgS, with the figure of merit zT even exceeding 1.4. Our analyses reveal that (i) the large weighted phase space and the quite low phonon group velocity result in the low κ L , (ii) the presence of flat band around the Fermi level combined with the large band gap causes the high S, and (iii) the small electron linewidths of the conduction band lead to a large relaxation time and thus a relatively high σ. These results support that α-HgS is a potential candidate for thermoelectric applications.

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Section: Resultssupporting

confidence: 87%

Low lattice thermal conductivity and good thermoelectric performance of cinnabar

Zhao

Dai

Lian

et al. 2017

Phys. Rev. Materials

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“…AgKO [250],AgNaO [250],AgORb [250],HgS [251],InN [252],NTl [253] Z4 × Z8 AlSc [254],AlY [255],B6Ca [256],B6Sr [256],BeTi [257] Br3CsGe [258],Br3CsPb [259],CsI3Sn [260] MgPd [261],PbSe [262],SnTe [263]…”

Section: Z2unclassified

Towards ideal topological materials: Comprehensive database searches using symmetry indicators

Tang,

Po,

Vishwanath

et al. 2018

Preprint

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Topological materials (TMs) showcase intriguing physical properties defying expectations based on conventional materials, and hold promise for the development of devices with new functionalities. While several theoretically proposed TMs have been experimentally confirmed, extensive experimental exploration of topological properties as well as applications in realistic devices have been held back due to the lack of excellent TMs in which interference from trivial Fermi surface states are minimized. We tackle this problem in the present work by applying our recently developed method of symmetry indicators to all non-magnetic compounds in the 230 space groups. An exhaustive database search reveals thousands of TM candidates. Of these, we highlight the excellent TMs, the 258 topological insulators and 165 topological crystalline insulators which have either noticeable full band gap or a considerable direct gap together with small trivial Fermi pockets. We also give a list of 489 topological semimetals with the band crossing points located near the Fermi level. All predictions obtained through standard generalized gradient approximation (GGA) calculations were cross-checked with the modified Becke-Johnson (MBJ) potential calculations, appropriate for narrow gap materials. With the electronic and optical behavior around the Fermi level dominated by the topologically non-trivial bands, these newly found TMs candidates open wide possibilities for realizing the promise of TMs in next-generation electronic devices.

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“…The α-phase of Ce 2 S 3 crystallizes in an orthorhombic lattice (crystallographic space group Pnma). The unit cell contains four formula units with two and three symmetry inequivalent cerium and sulfur ions, respectively [11]. Figure 1 The crystal structure of γ-Ce 2 S 3 has a body-centered cubic lattice.…”

Section: Crystal Structuresmentioning

confidence: 99%

“…The oxygen can be partialy replaced by sulfur. However, a complete substitution appears to be impossible [11], despite other assertions of Picon et al [10]. The structure of the β-phase has been described as complex, but has not been resolved.…”

Section: Introductionmentioning

confidence: 96%