Electronic structure of SrSn2As2 near the topological critical point

Rong, L.-Y.; Ma, Junzhang; Nie, Simin; Lin, Zijian; Li, Z.-L.; Bao, Futing; Kong, Ling-Yuan; Zhang, X.-Z.; Huang, Yaobo; Weng, Hongming; Qian, Tian; Ding, Hong; Tai, Renzhong

doi:10.1038/s41598-017-05386-x

Cited by 21 publications

(17 citation statements)

References 34 publications

(28 reference statements)

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“…Because of the vdW gap between the SnAs layers, it can be readily exfoliated through both mechanical and liquid-phase methods 9,10 . Besides, the sister compound SrSn 2 As 2 , having a crystal structure analogous to NaSn 2 As 2 , has been theoretically suggested to be very close to the topological critical point, hosting three-dimensional Dirac state at the Fermi level 11 , which was experimentally investigated by angle-resolved photoemission spectroscopy 12 . There are various structural analogues with conducting tin-pnictide (SnPn) layers, including Sn 4 Pn 3 13,14 and ASnPn 15–19 , as well as ASn 2 Pn 2 9,10,12,20–22 , where A denotes alkali or alkaline earth metal (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Na1−xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Goto

Miura

Moriyoshi

et al. 2018

Sci Rep

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Superconductors with a van der Waals (vdW) structure have attracted a considerable interest because of the possibility for truly two-dimensional (2D) superconducting systems. We recently reported NaSn2As2 as a novel vdW-type superconductor with transition temperature (Tc) of 1.3 K. Herein, we present the crystal structure and superconductivity of new material Na1−xSn2P2 with Tc = 2.0 K. Its crystal structure consists of two layers of a buckled honeycomb network of SnP, bound by the vdW forces and separated by Na ions, as similar to that of NaSn2As2. Amount of Na deficiency (x) was estimated to be 0.074(18) using synchrotron X-ray diffraction. Bulk nature of superconductivity was confirmed by the measurements of electrical resistivity, magnetic susceptibility, and specific heat. First-principles calculation using density functional theory shows that Na1−xSn2P2 and NaSn2As2 have comparable electronic structure, suggesting higher Tc of Na1−xSn2P2 resulted from increased density of states at the Fermi level due to Na deficiency. Because there are various structural analogues with tin-pnictide (SnPn) conducting layers, our results indicate that SnPn-based layered compounds can be categorized into a novel family of vdW-type superconductors, providing a new platform for studies on physics and chemistry of low-dimensional superconductors.

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Section: Introductionmentioning

confidence: 99%

Na1−xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Goto

Miura

Moriyoshi

et al. 2018

Sci Rep

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“…EuIn2P2 is therefore a semiconductor with a bandgap of ~0.4 eV. SrSn2As2 is also a topologically nontrivial material with band inversion, as reported by Gibson et al 28 and Rong et al 29 Figure 12 shows the densities of states (DOSs) of EuIn2As2, EuIn2P2, and SrSn2As2. The density of states in SrSn2As2 near the Fermi energy is larger than that in EuIn2As(P)2.…”

Section: First-principles Calculationsmentioning

confidence: 60%

“…23,24 EuIn2As2 and SrSn2As2 have also attracted considerable attention as topological materials. [26][27][28][29] Interestingly, topologically nontrivial electronic states and efficient thermoelectric properties are often observed in similar materials, such as (Bi,Sb)2(Te,Se)3 and (Pb,Sn)(Te,Se), because these compounds have the same required material features, including a narrow bandgap, heavy constituent elements, and large spin-orbit coupling. [30][31][32][33][34][35][36][37] Therefore, it is worth investigating the thermoelectric properties of EuIn2As(P)2 and SrSn2As2.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn₂As_2–xP_x (x = 0–2) and SrSn₂As₂

Shinozaki

Goto

Hoshi

et al. 2021

ACS Appl. Energy Mater.

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Zintl compounds containing Sb have been studied extensively because of their promising thermoelectric properties. In this study, we prepared As/P-based Zintl compounds, EuIn2As2−xPx (x = 0 to 2) and SrSn2As2, and examined their potential for use as thermoelectric materials. These compounds show p-type polarity with Hall carrier concentrations of ~10 19 cm −3 for EuIn2As2−xPx and ~10 21 cm −3 for SrSn2As2 at 300 K. The high carrier concentration of SrSn2As2 is likely owing to self-doping by hole-donating Sn vacancies. The electrical power factor reaches ~1 mW m 1 K 2 at ~600 K for EuIn2As2−xPx with x = 0.1 and 0.2, which is almost twice that of the end-member compounds (x = 0 and 2). The lattice thermal conductivity l is determined to be 1.6-2.0 W m 1 K 1 for EuIn2As2 and SrSn2As2 and 2.8 W m 1 K 1 for EuIn2P2 at 673 K. The dimensionless figure of merit reaches ZT = 0.29 at 773 K for EuIn2As2−xPx with x = 0.2 owing to the optimized carrier concentration and/or electronic structure, as well as a reduced lattice thermal conductivity in the solid solution. First-principles calculations show that EuIn2As2 and SrSn2As2 are topologically nontrivial materials with band inversion, while EuIn2P2 is a conventional semiconductor with a bandgap. The present study demonstrates that As/P-based Zintl compounds can also show promising thermoelectric properties, thus expanding the frontier for efficient thermoelectric materials.

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Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn2As2−xPx (X = 0 to 2) and SrSn2As2

Shinozaki¹,

Goto²,

Hoshi³

et al. 2021

Preprint

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Zintl compounds containing Sb have been studied extensively because of their promising thermoelectric properties. In this study, we prepared As/P-based Zintl compounds, EuIn2As2-xPx (x = 0 to 2) and SrSn2As2, and examined their potential for use as thermoelectric materials. These compounds show hole carrier concentrations of ~10^19 /cm3 for EuIn2As2-xPx and ~10^21 /cm3 for SrSn2As2 at 300 K. The high carrier concentration of SrSn2As2 is likely owing to self-doping by hole-donating Sn vacancies. The electrical power factor reaches ~1 mW/mK2 at ~600 K for EuIn2As2-xPx with x = 0.1 and 0.2. The lattice thermal conductivity is determined to be 1.6–2.0 W/mK for EuIn2As2 and SrSn2As2, and 2.8 W/mK for EuIn2P2 at 673 K. The dimensionless figure of merit reaches ZT = 0.29 at 773 K for EuIn2As2-xPx with x = 0.2. First-principles calculations show that EuIn2As2 and SrSn2As2 are topologically nontrivial materials with band inversion, while EuIn2P2 is a conventional semiconductor with a bandgap. The present study demonstrates that As/P-based Zintl compounds can also show promising thermoelectric properties, thus expanding the frontier for efficient thermoelectric materials.

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Electronic structure of SrSn2As2 near the topological critical point

Cited by 21 publications

References 34 publications

Na1−xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Na1−xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn₂As_2–xP_x (x = 0–2) and SrSn₂As₂

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn2As2−xPx (X = 0 to 2) and SrSn2As2

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Electronic structure of SrSn2As2 near the topological critical point

Cited by 21 publications

References 34 publications

Na1−xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Na1−xSn2P2 as a new member of van der Waals-type layered tin pnictide superconductors

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn2As2–xPx (x = 0–2) and SrSn2As2

Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn2As2−xPx (X = 0 to 2) and SrSn2As2

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Thermoelectric Properties of the As/P-Based Zintl Compounds EuIn₂As_2–xP_x (x = 0–2) and SrSn₂As₂