High-pressure phase transitions in CaTe and SrTe

Zimmer, H.-G.; Winzen, H.; Syassen, K.

doi:10.1103/physrevb.32.4066

Cited by 146 publications

(72 citation statements)

References 23 publications

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“…[49][50][51][52][53] CaTe undergoes a phase transition from NaCl-type structure at ambient conditions to CsCl-type structure at hydrostatic pressure about 33 GPa. 49,50 The structure of CaTe in CsCl-type is shown in Fig. 1a.…”

Section: Resultsmentioning

confidence: 99%

CaTe: a new topological node-line and Dirac semimetal

Du¹,

Tang²,

Wang³

et al. 2017

npj Quant Mater

115

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Combining first-principles calculations and effective model analysis, we predict that CaTe is a topological node-line semimetal in the absence of the spin-orbit coupling. Using a slab model, we obtain the nearly flat drumhead surface state near the Fermi level. When the spin-orbit coupling is included, three node lines will evolve into a pair of Dirac points along the M−R line. These Dirac points are robust and protected by the C 4 rotation symmetry. Once this crystal symmetry is broken, the Dirac points will be eliminated, and the system becomes a strong topological insulator.npj Quantum Materials (2017) 2:3 ; doi:10.1038/s41535-016-0005-4 INTRODUCTIONTopological insulator (TI) has attracted broad interest in the past 10 years. [1][2][3][4][5][6][7] The unique property of TI is that it is an insulator in the bulk but has exotic metallic surface states due to the topological order. More recently, the research on topological states has been extended to three-dimensional (3D) semimetal systems. [8][9][10][11][12] These systems could demonstrate many fascinating phenomena, such as Weyl fermion quantum transport and various Hall effects, [13][14][15][16] consequently become the rising stars of the field. Up to now, three kinds of topological semimetals have been discovered, i.e., 3D Dirac semimetal (DSM), 12,[17][18][19][20][21] Weyl semimetal (WSM), 8,9,22,23 and node-line semimetal (NLS). [24][25][26][27][28][29] The 3D DSM has four-fold degeneracy point, which can be viewed as the kiss of two Weyl fermions with opposite chiralities in the Brillouin zone (BZ). Protected by the crystal symmetry and time reversal symmetry, 3D DSMs can be robust against external perturbations. Several materials have been theoretically predicted to be 3D DSMs 12,17-21 and some of them have already been confirmed by experiments. [30][31][32][33] If one breaks the time reversal symmetry 8,22,23,34 or the inversion symmetry, 35-38 the 3D DSM will evolve into WSM. Very recently, the predictions about WSM state in TaAs family 37,38 have been confirmed experimentally. [39][40][41][42] Unlike DSM and WSM whose band crossing points distribute at separate k points in the BZ, for a NLS the crossing points around the Fermi level form a closed loop. Several compounds have been proposed as NLSs, including Mackay-Terrones crystals, 25 Bernal graphite, 43 hyperhoneycomb lattices, 44 and antiperovskite Cu 3 PdN 26,27 and Cu 3 NZn. 27 In the absence of spin-orbit coupling (SOC), time reversal symmetry together with inversion or mirror symmetry will guarantee the occurrence of node line in 3D BZ for systems with band inversion. [25][26][27]37,45,46 Same with TI and WSM, NLS also has a characteristic surface state, namely, drumhead-like state. 24-29 Such a 2D flat band surface state may become a route to achieve high temperature superconductivity. 47,48 As a result, it is of great impetus to search new NLS.In this study, based on first-principles calculations and effective model analysis, we propose that CaTe in CsCl-type structure is a NLS with drumhea...

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Section: Resultsmentioning

confidence: 99%

CaTe: a new topological node-line and Dirac semimetal

Du¹,

Tang²,

Wang³

et al. 2017

npj Quant Mater

115

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“…As a next step, we use the experimental data on lattice constant (a) [3,[5][6][7]40] the bulk modulus (B T ) [3], ionic (Ze), effective charge (e s * ), and the second-order aggregate elastic constant C 12 (C 44 ) [6,8] for determining the material parameters. The computed strontium SrX (X = O, S, Se, and Te) chalcogenides, material parameter of hardness (b), range (q), and non-central many-body forces arose due to charge transfer (f cti ) and covalency (f cov ) for SrX is illustrated in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…In view of the reported literature on technological important monochalcogenides as SrX (X = O, S, Se, and Te) [1][2][3][4][5][6][7][8][9][10][11][12], we notice that both the quantum calculations and the lattice model calculations predict the pressure-induced ground state properties and no efforts have been made to explore the temperature-dependent elastic, thermal, and thermodynamical properties of these chalcogenides. In view of these, we made systematic efforts to investigate (a) pressure-induced, and (b) temperature-induced properties.…”

Section: Introductionmentioning

confidence: 99%

“…The Energy-dispersive X-ray diffraction (EDXD) observes the transition pressure (P T ) in SrO = 36 GPa [3,4], SrS = 18 GPa [3,7], SrSe = 14 GPa [3], and SrTe = 12 GPa, respectively [3,5]. A percentage volume collapse at P T in going from (B1 to B2) of about 13.0 in SrO [3,4], 11.4 in SrS [3,7], 10.7 in SrSe [3], and 11.1 in SrTe [3,5] is reported using high-pressure X-rays diffraction studies. The elastic stiffness constant is obtained using ultrasonic pulse-echo technique [6].…”

Section: Introductionmentioning

confidence: 99%

“…The full-potential linear augmented plane-wave method (FP-LAPW) has been exercised to probe the ground state properties such as lattice parameter, bulk modulus, and its pressure derivative, elastic constant and structural stability of the compound SrS, SrSe, and SrTe, respectively [1][2][3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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High-pressure and temperature-induced structural, elastic, and thermodynamical properties of strontium chalcogenides

et al. 2016

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Pressure-and temperature-dependent mechanical, elastic, and thermodynamical properties of rock salt to CsCl structures in semiconducting SrX (X = O, S, Se, and Te) chalcogenides are presented based on model interatomic interaction potential with emphasis on charge transfer interactions, covalency effect, and zero point energy effects apart from long-range Coulomb, short-range overlap repulsion extended and van der Waals interactions. The developed potential with non-central forces validates the Cauchy discrepancy among elastic constants. The volume collapse (V P /V 0 ) in terms of compressions in SrX at higher pressure indicates the mechanical stiffening of lattice. The expansion of SrX lattice is inferred from steep increase in V T /V 0 and is attributed to thermal softening of SrX lattice. We also present the results for the temperaturedependent behaviors of hardness, heat capacity, and thermal expansion coefficient. From the Pugh's ratio (/ = B T /G H ), the Poisson's ratio (m) and the Cauchy's pressure (C 12 -C 44 ), we classify SrO as ductile but SrS, SrSe, and SrTe are brittle material. To our knowledge these are the first quantitative theoretical prediction of the pressure and temperature dependence of mechanical stiffening, thermally softening, and brittle nature of SrX (X = O, S, Se, and Te) and still await experimental confirmations.

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Electronic and structural properties of strontium chalcogenides SrS, SrSe and SrTe

Rached¹,

Rabah

Benkhettou

et al. 2004

Physica Status Solidi (b)

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We present the results of a first-principles study of the electronic and structural properties of strontium chalcogenides, SrS, SrSe and SrTe. The computational method is based on the full-potential linear muffintin orbitals method (FP-LMTO) augmented by a plane-wave basis (PLW). The exchange and correlation energy is described in the local density approximation (LDA) using the Perdew-Wang parameterization including a generalized gradient approximation (GGA). The calculated results of the structural properties are given for the NaCl (B1) and CsCl (B2) structures. We have also carried out band-structure calculations for the three considered compound, but only for the NaCl (B1) structure. A reasonable agreement is found from the comparison of our results with other theoretical calculations and experimental data.

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High-pressure phase transitions in CaTe and SrTe

Cited by 146 publications

References 23 publications

CaTe: a new topological node-line and Dirac semimetal

CaTe: a new topological node-line and Dirac semimetal

High-pressure and temperature-induced structural, elastic, and thermodynamical properties of strontium chalcogenides

Electronic and structural properties of strontium chalcogenides SrS, SrSe and SrTe

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