Dirac semimetal phase in hexagonal LiZnBi

Cao, Wendong; Tang, Peizhe; Xu, Yong; Wu, Jian; Gu, Bing-Lin; Duan, Wenhui

doi:10.1103/physrevb.96.115203

Cited by 36 publications

(24 citation statements)

References 51 publications

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“…In this sense, the Dirac points are similar to the known centrosymmetric Dirac materials Na 3 Bi [11], but should be distinguished from semimetals with essential fourfold degenerate Dirac points, mandated by crystal symmetry and located at high-symmetry points, such as BiO 2 [10]. Similar noncentrosymmetric Dirac semimetals, arising due to band inversion, have been proposed in YbAuSb [25] and LiZnBi [26] with LiGaGe-type structure.…”

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confidence: 71%

Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal ABC Crystals

et al. 2018

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We propose that the noncentrosymmetric LiGaGe-type hexagonal ABC crystal SrHgPb realizes a new type of topological semimetal that hosts both Dirac and Weyl points in momentum space. The symmetry-protected Dirac points arise due to a band inversion and are located on the sixfold rotation z axis, whereas the six pairs of Weyl points related by sixfold symmetry are located on the perpendicular k_{z}=0 plane. By studying the electronic structure as a function of the buckling of the HgPb layer, which is the origin of inversion symmetry breaking, we establish that the coexistence of Dirac and Weyl fermions defines a phase separating two topologically distinct Dirac semimetals. These two Dirac semimetals are distinguished by the Z_{2} index of the k_{z}=0 plane and the corresponding presence or absence of 2D Dirac fermions on side surfaces. We formalize our first-principles calculations by deriving and studying a low-energy model Hamiltonian describing the Dirac-Weyl semimetal phase. We conclude by proposing several other materials in the noncentrosymmetric ABC material class, in particular SrHgSn and CaHgSn, as candidates for realizing the Dirac-Weyl semimetal.

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confidence: 71%

Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal ABC Crystals

et al. 2018

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“…2 with PCM has been done to further confirm the presence of quantum confinement effect and quantitative estimation of size of SiNWs in samples n À and p À . [17,19,[46][47][48][49] The fitting of Raman lines has been done by a general Raman-Fano line-shape given by Eqn (3) below: [44] I…”

Section: Resultsmentioning

confidence: 99%

Raman spectroscopy for study of interplay between phonon confinement and Fano effect in silicon nanowires

Saxena

Borah

Kumar

et al. 2015

J. Raman Spectrosc.

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A combined effect of doping (type and species) and size on Raman scattering from silicon (Si) nanowires (NWs) has been presented here to study interplay between quantum confinement and Fano effects. The SiNWs prepared from low doping Si wafers show only confinement effect, as evident from the asymmetry in the Raman line‐shape, irrespective of the doping type. On the other hand SiNWs prepared from wafer with high doping shows the presence of electron–phonon interaction in addition to the phonon confinement effect as revealed from the presence of asymmetry and antiresonence in the corresponding Raman spectra. This combined effect induces an extra asymmetry in the lower energy side of Raman peak for n‐type SiNWs whereas the asymmetry flips from lower energy side to the higher energy side of the Raman peak in p‐type SiNWs. Such an interplay can be represented by considering a general Fano‐Raman line‐shape equation to take care of the combined effect in SiNWs. Copyright © 2015 John Wiley & Sons, Ltd.

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“…This signifies that the photons can be efficiently trapped either at the interface of PdSe 2 /pyramid Si or inside the Si, which could be eventually absorbed to generate carriers. The unique optical phenomenon is usually termed as light trapping effect [25] or resonant absorption, [26,27] which is highly beneficial for light detection. Please note that as the wavelength increases to 1300 nm (Figure 2d-f), a strong electric field could also be observed inside the pyramid Si.…”

Section: Introductionmentioning

confidence: 99%

Light Confinement Effect Induced Highly Sensitive, Self‐Driven Near‐Infrared Photodetector and Image Sensor Based on Multilayer PdSe₂/Pyramid Si Heterojunction

Liang

Zhao

Jiang

et al. 2019

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In this study, a highly sensitive and self‐driven near‐infrared (NIR) light photodetector based on PdSe2/pyramid Si heterojunction arrays, which are fabricated through simple selenization of predeposited Pd nanofilm on black Si, is demonstrated. The as‐fabricated hybrid device exhibits excellent photoresponse performance in terms of a large on/off ratio of 1.6 × 105, a responsivity of 456 mA W−1, and a high specific detectivity of up to 9.97 × 1013 Jones under 980 nm illumination at zero bias. Such a relatively high sensitivity can be ascribed to the light trapping effect of the pyramid microstructure, which is confirmed by numerical modeling based on finite‐difference time domain. On the other hand, thanks to the broad optical absorption properties of PdSe2, the as‐fabricated device also exhibits obvious sensitivity to other NIR illuminations with wavelengths of 1300, 1550, and 1650 nm, which is beyond the photoresponse range of Si‐based devices. It is also found that the PdSe2/pyramid Si heterojunction device can also function as an NIR light sensor, which can readily record both “tree” and “house” images produced by 980 and 1300 nm illumination, respectively.

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Dirac semimetal phase in hexagonal LiZnBi

Cited by 36 publications

References 51 publications

Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal ABC Crystals

Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal ABC Crystals

Raman spectroscopy for study of interplay between phonon confinement and Fano effect in silicon nanowires

Light Confinement Effect Induced Highly Sensitive, Self‐Driven Near‐Infrared Photodetector and Image Sensor Based on Multilayer PdSe₂/Pyramid Si Heterojunction

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Dirac semimetal phase in hexagonal LiZnBi

Cited by 36 publications

References 51 publications

Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal ABC Crystals

Dirac-Weyl Semimetal: Coexistence of Dirac and Weyl Fermions in Polar Hexagonal ABC Crystals

Raman spectroscopy for study of interplay between phonon confinement and Fano effect in silicon nanowires

Light Confinement Effect Induced Highly Sensitive, Self‐Driven Near‐Infrared Photodetector and Image Sensor Based on Multilayer PdSe2/Pyramid Si Heterojunction

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Product

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Light Confinement Effect Induced Highly Sensitive, Self‐Driven Near‐Infrared Photodetector and Image Sensor Based on Multilayer PdSe₂/Pyramid Si Heterojunction