Anorganische Hochpolymere

Krebs, H.

doi:10.1002/ange.19580702002

Cited by 32 publications

(15 citation statements)

References 36 publications

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“…4(a) the bonding structure of a Te atom in the crystal occupying the center of a distorted octahedron with its six neighbors on multiple helices, where fr i g and fR i g denote NN intrachain and next NN interchain bond lengths. The octahedral basal plane is spanned by r 1 , r 2 , R 2 , R 3 , and the perpendicular R 3 -R 4 axis aligns along a mesomeric chain [26]. The equilibrium intrachain # and interchain angles are 101 and 167.5 , respectively.…”

Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

“…interchain bonds [27]. Although only weakly coupled, these mesomeric chains knit together atoms from different helices and help stabilize the crystal through two mesomeric mechanisms [26] as follows. (1) Interactions between occupied orbitals: (a) The ji-ji interaction, where ji denotes the jsi-derived semicore states [$ À 12 eV in Fig.…”

Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

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Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

et al. 2013

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Employing ab initio electronic structure calculations, we predict that trigonal tellurium consisting of weakly interacting helical chains undergoes a trivial insulator to strong topological insulator (metal) transition under shear (hydrostatic or uniaxial) strain. The transition is demonstrated by examining the strain evolution of the band structure, the topological Z 2 invariant and the concomitant band inversion. The underlying mechanism is the depopulation of the lone-pair orbitals associated with the valence band via proper strain engineering. Thus, Te becomes the prototype of a novel family of chiral-based three-dimensional topological insulators with important implications in spintronics, magneto-optics, and thermoelectrics. DOI: 10.1103/PhysRevLett.110.176401 PACS numbers: 71.15.Ap, 72.25.Dc, 73.20.At, 73.43.Nq The recent discovery of three-dimensional (3D) topological insulators (TIs) has sparked intense efforts in the search for novel materials that exhibit this new quantum-mechanical state of matter driven by strong spin-orbit coupling, which leads to the appearance of spin-momentum-locked topologically protected surface states with a Dirac-cone energy dispersion [1][2][3]. Ongoing research efforts focus primarily on the prototypical family of Bi 2 Te 3 , Bi 2 Se 3 , and Sb 2 Te 3 3D TIs, which exhibit a quintuple layered structure along the c axis of the hexagonal lattice. The intra-and interlayer coupling within one quintuple layer is covalentlike while the interaction between two quintuple layers is much weaker, predominantly of the van der Waals type [3][4][5].The heavier group-VI elements selenium and tellurium are ubiquitous in most of the recently discovered binary or ternary TIs and exhibit a wide variety of interesting properties under pressure. They undergo complex structural changes [6], exhibit semiconductor-to-metal transitions [7], have unusual melting curves [8], and some of their high-pressure phases are superconducting at low temperatures [6]. At ambient conditions, tellurium has a trigonal crystal structure (Te-I) with space group D 4 3 consisting of weakly interacting infinite helical chains arranged in a hexagonal array, which spiral around axes parallel to c. The unit cell shown in Fig. 1(a) has three atoms at the positions (u, 0, 0), (0, u, 1=3), and ( " u, " u, 2=3) in units of the lattice vectors [9], where u is the internal atomic position parameter. Each atom forms strong covalentlike intrachain bonds with its two nearest neighbors (NNs) and weak van der Waals-like interchain bonds with its four next NNs, with bond lengths of r ¼ 2:91 # A and R ¼ 3:43 # A, respectively. This unique feature is reflected in liquid-state studies of Te which showed that the chain structure is retained above the melting temperature [8].In this Letter we predict that Te-I, a noncentrosymmetric material, becomes a strong TI or topological metal (TM) under application of shear or uniform and uniaxial strain, respectively. In most reported TIs to date, the band inversion and the gap closing occur n...

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Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Section: H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

et al. 2013

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“…While Se and Te have the same hexagonal structure, [8][9][10] it is well known that, in contrast to Se, which is a good glass-forming element, Te is impossible to vitrify even when using fast quenching. Indeed, the Te melt, which is very fluid, possesses a strong metallic character.…”

Section: Introductionmentioning

confidence: 99%

A Family of Far‐Infrared‐Transmitting Glasses in the Ga–Ge–Te System for Space Applications

Danto¹,

Houizot²,

Boussard‐Plédel³

et al. 2006

Adv Funct Materials

165

113

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Conditions of formation of bulk tellurium chalcogenide glasses, containing 70–80 at % Te associated to Ga and Ge are described. The characteristic temperatures are measured: the glass‐transition temperature, Tg, is situated in the range 140–185 °C and the difference Tx – Tg, where Tx is the onset crystallization temperature, is in the range 76–113 °C. Moreover, the optical transmission window is exceptional, ranging from 1.99 μm in the bandgap up to 28 μm in the phonon region.Developed within the framework of requirements for the Darwin mission (a search for and study of extrasolar planets), feasibility of infrared optical fibers formed from these glasses is studied. Drawing experiments are conducted with the glass Ga2‐Ge3Te15, which possesses the maximum Tx – Tg, and a first optical fiber is presented.

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“…Sie enthiilt Heine Ringe (Se6 oder Sea), lange unperiodisch gebaute Ketten und mehr oder weniger geordnete hexagonale Gebiete [1][2][3]. Die Erh/Shung der Schmelztemperatur T~ bewirkt eine Abnahme des Gehaltes an kleinen Ringen (z.B.…”

Section: W Swiatkowsldunclassified

“…Die Erh/Shung der Schmelztemperatur T~ bewirkt eine Abnahme des Gehaltes an kleinen Ringen (z.B. von 41 auf 23% mit zunahme von Tt von 220 auf 400 ~ und an Gebieten, die bei Tf > 350 ~ verschwinden [1,2,4].…”

Section: W Swiatkowsldunclassified

DTA-untersuchungen der Kristallisation des glasigen Selens

Świątkowski

1991

Journal of Thermal Analysis

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The DTA method has been used for determination of the initial crystallization temperature TA for the vitreous selenium samples remelted in the different temperatures Tf. The decrease of the TA values with increase of Tf temperatures was observed. These results may be explained by assumption that the increase of concentration of the chains accelerates the nucleation process in the vitreous selenium.

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Anorganische Hochpolymere

Cited by 32 publications

References 36 publications

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

Novel Family of Chiral-Based Topological Insulators: Elemental Tellurium under Strain

A Family of Far‐Infrared‐Transmitting Glasses in the Ga–Ge–Te System for Space Applications

DTA-untersuchungen der Kristallisation des glasigen Selens

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