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Synthesis and characterization of 3D topological insulators: a case TlBi(S 1 − x Se x ) 2

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ABSTRACT

In this article, practical methods for synthesizing Tl-based ternary III-V-VI2 chalcogenide TlBi(SSex)2 are described in detail, along with characterization by x-ray diffraction and charge transport properties. The TlBi(SSex)2 system is interesting because it shows a topological phase transition, where a topologically nontrivial phase changes to a trivial phase without changing the crystal structure qualitatively. In addition, Dirac semimetals whose bulk band structure shows a Dirac-like dispersion are considered to exist near the topological phase transition. The technique shown here is also generally applicable for other chalcogenide topological insulators, and will be useful for studying topological insulators and related materials.

No MeSH data available.


(a) Lattice constants determined from power XRD are plotted as functions of the Se content. (b) Powder XRD patterns. Normalized intensity profiles of the (018) and (110) peaks in the powdered TlBi(SSex)2 single crystals for a series of Se concentrations; the (018) peak reflects both the in-plane and out-of-plane periodicities, whereas the (110) peak reflects solely the in-plane periodicity. Taken from [16].
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Figure 3: (a) Lattice constants determined from power XRD are plotted as functions of the Se content. (b) Powder XRD patterns. Normalized intensity profiles of the (018) and (110) peaks in the powdered TlBi(SSex)2 single crystals for a series of Se concentrations; the (018) peak reflects both the in-plane and out-of-plane periodicities, whereas the (110) peak reflects solely the in-plane periodicity. Taken from [16].

Mentions: Figures 2(c) and (d) show photographs of TlBiSe2 crystals. The obtained crystals are easily cleavable, and the grain size is as long as ∼5 mm along the cleavage plane. Figure 2(e) shows the Laue picture taken with respect to the cleavage plane. This clearly shows the three-fold symmetry of the system, and the result is consistent with the structure of TlBiSe2. The lattice constants of TlBi(SSex)2 are obtained by both single-crystal and powder x-ray diffraction (XRD), as shown in figure 3. If I take a hexagonal lattice, –0.410 nm and for x = 1.0 to 0.0. It is important to note that the lattice parameters change continuously with changing x, and the crystallographic structure does not change.


Synthesis and characterization of 3D topological insulators: a case TlBi(S 1 − x Se x ) 2
(a) Lattice constants determined from power XRD are plotted as functions of the Se content. (b) Powder XRD patterns. Normalized intensity profiles of the (018) and (110) peaks in the powdered TlBi(SSex)2 single crystals for a series of Se concentrations; the (018) peak reflects both the in-plane and out-of-plane periodicities, whereas the (110) peak reflects solely the in-plane periodicity. Taken from [16].
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Related In: Results  -  Collection

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Figure 3: (a) Lattice constants determined from power XRD are plotted as functions of the Se content. (b) Powder XRD patterns. Normalized intensity profiles of the (018) and (110) peaks in the powdered TlBi(SSex)2 single crystals for a series of Se concentrations; the (018) peak reflects both the in-plane and out-of-plane periodicities, whereas the (110) peak reflects solely the in-plane periodicity. Taken from [16].
Mentions: Figures 2(c) and (d) show photographs of TlBiSe2 crystals. The obtained crystals are easily cleavable, and the grain size is as long as ∼5 mm along the cleavage plane. Figure 2(e) shows the Laue picture taken with respect to the cleavage plane. This clearly shows the three-fold symmetry of the system, and the result is consistent with the structure of TlBiSe2. The lattice constants of TlBi(SSex)2 are obtained by both single-crystal and powder x-ray diffraction (XRD), as shown in figure 3. If I take a hexagonal lattice, –0.410 nm and for x = 1.0 to 0.0. It is important to note that the lattice parameters change continuously with changing x, and the crystallographic structure does not change.

View Article: PubMed Central - PubMed

ABSTRACT

In this article, practical methods for synthesizing Tl-based ternary III-V-VI2 chalcogenide TlBi(SSex)2 are described in detail, along with characterization by x-ray diffraction and charge transport properties. The TlBi(SSex)2 system is interesting because it shows a topological phase transition, where a topologically nontrivial phase changes to a trivial phase without changing the crystal structure qualitatively. In addition, Dirac semimetals whose bulk band structure shows a Dirac-like dispersion are considered to exist near the topological phase transition. The technique shown here is also generally applicable for other chalcogenide topological insulators, and will be useful for studying topological insulators and related materials.

No MeSH data available.