Prediction of a Weyl semimetal in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Hg</mml:mtext><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi><mml:mo>−</mml:mo><mml:mi>y</mml:mi></mml:mrow></mml:msub></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Cd</mml:mtext><mml:mi>x</mml:mi></mml:msub></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>Mn</mml:mtext><mml:mi>y</mml:mi></mml:msub>

Bulmash, Daniel; Liu, Chao Xing; Qi, Xiao Liang

doi:10.1103/physrevb.89.081106

Cited by 142 publications

(113 citation statements)

References 24 publications

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“…Weyl and 3D Dirac semimetal phases have been predicted in a variety of existing or tailored systems as follows: (i) Pyrochlore iridates could host 24 Weyl nodes through the interplay of SOC and strong electron correlations (Wan et al 2011); (ii) Ferromagnetic HgCr2Se4 spinel with nodes protected by C4 point group symmetry (Xu, Weng, et al 2011;); (iii) Crystalline Cd3As2 (Wang, Weng, et al 2013) and A3Bi (A = Na, K, Rb) (Wang, Sun, et al 2012); (iv) β-cristobalite BiO2; (Young et al 2012) (v) strained Hg1-x-yCdxMnyTe under magnetic field (Bulmash, Liu, and Qi 2014); (vi) TlBiSe2 (Singh et al 2012); (vii) Heterostructure of magnetically doped 3D TI and normal insulator (Burkov and Balents 2011b); and, (viii) A superlattice of alternating layers with odd and even parity orbitals. Experimentally realized 3D Dirac semimetals so far are Cd3As2 Borisenko et al 2014;Ali et al 2014) and Na3Bi .…”

Section: Ivh Weyl and 3d Dirac Semimetalsmentioning

confidence: 99%

Colloquium: Topological band theory

2016

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The first-principles band theory paradigm has been a key player not only in the process of discovering new classes of topologically interesting materials, but also for identifying salient characteristics of topological states, enabling direct and sharpened confrontation between theory and experiment. We begin this review by discussing underpinnings of the topological band theory, which basically involves a layer of analysis and interpretation for assessing topological properties of band structures beyond the standard band theory construct. Methods for evaluating topological invariants are delineated, including crystals without inversion symmetry and interacting systems. The extent to which theoretically predicted properties and protections of topological states have been verified experimentally is discussed, including work on topological crystalline insulators, disorder/interaction driven topological insulators (TIs), topological superconductors, Weyl semimetal phases, and topological phase transitions. Successful strategies for new materials discovery process are outlined. A comprehensive survey of currently predicted 2D and 3D topological materials is provided. This includes binary, ternary and quaternary compounds, transition metal and f-electron materials, Weyl and 3D Dirac semimetals, complex oxides, organometallics, skutterudites and antiperovskites. Also included is the emerging area of 2D atomically thin films beyond graphene of various elements and their alloys, functional thin films, multilayer systems, and ultra-thin films of 3D TIs, all of which hold exciting promise of wide-ranging applications. We conclude by giving a perspective on research directions where further work will broadly benefit the topological materials field.

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Section: Ivh Weyl and 3d Dirac Semimetalsmentioning

confidence: 99%

Colloquium: Topological band theory

2016

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“…Early theoretical proposals require either magnetic ordering in sufficiently large domains (3, 23-26) or fine-tuning of the chemical composition to within 5% in an alloy (23,(25)(26)(27), which proved demanding in real experiments. Recently, our group and a concurrent group successfully proposed the first, to our knowledge, experimentally feasible Weyl semimetal candidate in TaAs material class (28,29).…”

mentioning

confidence: 99%

New type of Weyl semimetal with quadratic double Weyl fermions

Huang

Belopolski

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

362

248

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Weyl semimetals have attracted worldwide attention due to their wide range of exotic properties predicted in theories. The experimental realization had remained elusive for a long time despite much effort. Very recently, the first Weyl semimetal has been discovered in an inversion-breaking, stoichiometric solid TaAs. So far, the TaAs class remains the only Weyl semimetal available in real materials. To facilitate the transition of Weyl semimetals from the realm of purely theoretical interest to the realm of experimental studies and device applications, it is of crucial importance to identify other robust candidates that are experimentally feasible to be realized. In this paper, we propose such a Weyl semimetal candidate in an inversionbreaking, stoichiometric compound strontium silicide, SrSi 2 , with many new and novel properties that are distinct from TaAs. We show that SrSi 2 is a Weyl semimetal even without spin-orbit coupling and that, after the inclusion of spin-orbit coupling, two Weyl fermions stick together forming an exotic double Weyl fermion with quadratic dispersions and a higher chiral charge of ±2. Moreover, we find that the Weyl nodes with opposite charges are located at different energies due to the absence of mirror symmetry in SrSi 2 , paving the way for the realization of the chiral magnetic effect. Our systematic results not only identify a much-needed robust Weyl semimetal candidate but also open the door to new topological Weyl physics that is not possible in TaAs. topological insulator | Weyl fermion | Fermi arc | chiral magnetic effect A nalogous to graphene and the 3D topological insulator, Weyl semimetals are believed to open the next era in condensed matter physics (1-8). A Weyl semimetal represents an elegant example of the correspondence between condensed matter and high-energy physics because its low-energy excitations, the Weyl fermions, are massless particles that have played an important role in quantum field theory and the standard model but have not been observed as a fundamental particle in nature. A Weyl semimetal is also a topologically nontrivial metallic phase of matter extending the classification of topological phases beyond insulators (3-6). The nontrivial topological nature guarantees the existence of exotic Fermi arc electron states on the surface of a Weyl semimetal. In contrast with a topological insulator where the bulk is gapped and only the Dirac cones on its surfaces are of interest, in a Weyl semimetal, both the Weyl fermions in the bulk and the Fermi arcs on the surface are fundamentally new and are expected to give rise to a wide range of exotic phenomena (9-22).For many years, research on Weyl semimetals has been held back due to the lack of experimentally feasible candidate materials. Early theoretical proposals require either magnetic ordering in sufficiently large domains (3, 23-26) or fine-tuning of the chemical composition to within 5% in an alloy (23,(25)(26)(27), which proved demanding in real experiments. Recently, our group and a concurrent group s...

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“…Many theoretical proposals exist for realizing Weyl semimetals that possess interesting physical properties, such as discontinuous Fermi arcs and negative magnetoresistance due to the chiral anomaly. 4,[6][7][8][9][10][19][20][21][22][23][24][25][26][27][28][29]31,32,34 A Weyl node with definite chirality is associated with the Berry curvature and may be thought of as realizations of magnetic monopoles in momentum space.…”

Section: Introductionmentioning

confidence: 99%

Fermi surface interconnectivity and topology in Weyl fermion semimetals TaAs, TaP, NbAs, and NbP

et al. 2015

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The family of binary compounds including TaAs, TaP, NbAs, and NbP was recently discovered as the first realization of Weyl semimetals. In order to develop a comprehensive description of the charge carriers in these Weyl semimetals, we performed a detailed and systematic electronic band structure calculations which reveal the nature of Fermi surfaces and their complex interconnectivity in TaAs, TaP, NbAs, and NbP. Our work report the first comparative and comprehensive study of Fermi surface topology and band structure details of all known members of the Weyl semimetal family, and hence provides the fundamental knowledge for realizing the many predicted exotic topological quantum physics of Weyl semimetals based on the TaAs class of materials.

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Prediction of a Weyl semimetal inHg1−x−yCdxMny

Cited by 142 publications

References 24 publications

Colloquium: Topological band theory

Colloquium: Topological band theory

New type of Weyl semimetal with quadratic double Weyl fermions

Fermi surface interconnectivity and topology in Weyl fermion semimetals TaAs, TaP, NbAs, and NbP

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