scholarly journals Composite Weyl semimetal as a parent state for three-dimensional topologically ordered phases

2018 ◽  
Vol 98 (20) ◽  
Author(s):  
Eran Sagi ◽  
Ady Stern ◽  
David F. Mross
Keyword(s):  
Three Dimensional ◽  
Weyl Semimetal ◽  
Parent State ◽  
Ordered Phases

scholarly journals Cobalt-based magnetic Weyl semimetals with high-thermodynamic stabilities

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Wei Luo ◽  
Yuma Nakamura ◽  
Jinseon Park ◽  
Mina Yoon
Keyword(s):  
Tight Binding ◽  
Three Dimensional ◽  
Interlayer Coupling ◽  
First Principles Calculation ◽  
Optimization Approach ◽  
Binding Model ◽  
Nodal Lines ◽  
Weyl Semimetal ◽  
Topological Quantum ◽  
First Time

AbstractRecent experiments identified Co3Sn2S2 as the first magnetic Weyl semimetal (MWSM). Using first-principles calculation with a global optimization approach, we explore the structural stabilities and topological electronic properties of cobalt (Co)-based shandite and alloys, Co3MM’X2 (M/M’ = Ge, Sn, Pb, X = S, Se, Te), and identify stable structures with different Weyl phases. Using a tight-binding model, for the first time, we reveal that the physical origin of the nodal lines of a Co-based shandite structure is the interlayer coupling between Co atoms in different Kagome layers, while the number of Weyl points and their types are mainly governed by the interaction between Co and the metal atoms, Sn, Ge, and Pb. The Co3SnPbS2 alloy exhibits two distinguished topological phases, depending on the relative positions of the Sn and Pb atoms: a three-dimensional quantum anomalous Hall metal, and a MWSM phase with anomalous Hall conductivity (~1290 Ω−1 cm−1) that is larger than that of Co2Sn2S2. Our work reveals the physical mechanism of the origination of Weyl fermions in Co-based shandite structures and proposes topological quantum states with high thermal stability.

scholarly journals Emergent chiral symmetry in a three-dimensional interacting Dirac liquid

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
András L. Szabó ◽  
Bitan Roy
Keyword(s):  
Fixed Points ◽  
Chiral Symmetry ◽  
Rotational Symmetry ◽  
Three Dimensional ◽  
Spatial Dimension ◽  
Dirac Fermions ◽  
Electronic Interactions ◽  
Emergent Phenomena ◽  
Ordered Phases ◽  
The Stability

Abstract We compute the effects of strong Hubbardlike local electronic interactions on three-dimensional four-component massless Dirac fermions, which in a noninteracting system possess a microscopic global U(1) ⊗ SU(2) chiral symmetry. A concrete lattice realization of such chiral Dirac excitations is presented, and the role of electron-electron interactions is studied by performing a field theoretic renormalization group (RG) analysis, controlled by a small parameter ϵ with ϵ = d−1, about the lower-critical one spatial dimension. Besides the noninteracting Gaussian fixed point, the system supports four quantum critical and four bicritical points at nonvanishing interaction couplings ∼ ϵ. Even though the chiral symmetry is absent in the interacting model, it gets restored (either partially or fully) at various RG fixed points as emergent phenomena. A representative cut of the global phase diagram displays a confluence of scalar and pseudoscalar excitonic and superconducting (such as the s-wave and p-wave) mass ordered phases, manifesting restoration of (a) chiral U(1) symmetry between two excitonic masses for repulsive interactions and (b) pseudospin SU(2) symmetry between scalar or pseudoscalar excitonic and superconducting masses for attractive interactions. Finally, we perturbatively study the effects of weak rotational symmetry breaking on the stability of various RG fixed points.

scholarly journals Exceptional topological insulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Michael Denner ◽  
Anastasiia Skurativska ◽  
Frank Schindler ◽  
Mark H. Fischer ◽  
Ronny Thomale ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Three Dimensional ◽  
Surface States ◽  
Exceptional Point ◽  
Weyl Semimetal ◽  
Complex Eigenvalues ◽  
Topological State ◽  
Single Sheet ◽  
Bulk Energy ◽  
State Of Matter

AbstractWe introduce the exceptional topological insulator (ETI), a non-Hermitian topological state of matter that features exotic non-Hermitian surface states which can only exist within the three-dimensional topological bulk embedding. We show how this phase can evolve from a Weyl semimetal or Hermitian three-dimensional topological insulator close to criticality when quasiparticles acquire a finite lifetime. The ETI does not require any symmetry to be stabilized. It is characterized by a bulk energy point gap, and exhibits robust surface states that cover the bulk gap as a single sheet of complex eigenvalues or with a single exceptional point. The ETI can be induced universally in gapless solid-state systems, thereby setting a paradigm for non-Hermitian topological matter.

Bereziskii-Kosterlitz-Thouless transition in the Weyl system PtBi2

2021 ◽  
Author(s):  
Arthur Veyrat ◽  
Valentin Labracherie ◽  
Rohith Acharya ◽  
Dima Bashlakov ◽  
Federico Caglieris ◽  
...  
Keyword(s):  
Condensed Matter ◽  
Three Dimensional ◽  
Spin Orbit Coupling ◽  
Two Dimensional ◽  
Pairing Mechanism ◽  
Critical Fields ◽  
Weyl Semimetal ◽  
Superconducting Coherence Length ◽  
Low Dimensional ◽  
Strong Spin

Abstract Symmetry breaking in topological matter became, in the last decade, a key concept in condensed matter physics to unveil novel electronic states. In this work, we reveal that broken inversion symmetry and strong spin-orbit coupling in trigonal PtBi2 lead to a Weyl semimetal band structure, with unusually robust two-dimensional superconductivity in thin fims. Transport measurements show that high-quality PtBi2 crystals are three-dimensional superconductors (Tc≈600 mK) with an isotropic critical field (Bc≈50 mT). Remarkably, we evidence in a rather thick flake (60 nm), exfoliated from a macroscopic crystal, the two-dimensional nature of the superconducting state, with a critical temperature Tc≈370 mK and highly-anisotropic critical fields. Our results reveal a Berezinskii-Kosterlitz-Thouless transition with TBKT≈310 mK and with a broadening of Tc due to inhomogenities in the sample. Due to the very long superconducting coherence length ξ in PtBi2, the vortex-antivortex pairing mechanism can be studied in unusually-thick samples (at least five times thicker than for any other two-dimensional superconductor), making PtBi2 an ideal platform to study low dimensional superconductivity in a topological semimetal.

scholarly journals Three-Dimensional Electronic Structure of the Type-II Weyl Semimetal WTe2

2017 ◽  
Vol 119 (2) ◽  
Author(s):  
Domenico Di Sante ◽  
Pranab Kumar Das ◽  
C. Bigi ◽  
Z. Ergönenc ◽  
N. Gürtler ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Three Dimensional ◽  
Type Ii ◽  
Weyl Semimetal

A Shift-Lattice Interpretation of Structures in the Au4Mn Region of the Au-Mn System

1996 ◽  
Vol 49 (8) ◽  
pp. 873
Author(s):  
RJD Tilley ◽  
RP Williams
Keyword(s):  
Three Dimensional ◽  
One Dimensional ◽  
Ordered Phases ◽  
The Matrix ◽  
Unit Cells ◽  
The Face ◽  
Cubic Structure ◽  
Diffraction Patterns

The structures of a number of ordered phases in the Au-Mn system derived from the face- centred cubic structure of Au4Mn have been described in a systematic manner by use of shift-lattice distributions of the manganese atoms throughout the matrix of the alloys. The simplest structures are describable in terms of one-dimensional shift lattices, but many are best treated as two- or three-dimensional shift lattices. This approach has allowed structural correlations to be presented that have not been described previously and the variation in stoichiometry of these phases to be accounted for without recourse to defect populations. The diffraction patterns of such structures are also discussed, especially incommensurate patterns from materials with 'infinitely large' crystallographic unit cells.

scholarly journals Three-dimensional structure of the ordered phases of Hg on Cu(001)

1992 ◽  
Vol 45 (7) ◽  
pp. 3708-3717 ◽  
Author(s):  
Wei Li ◽  
Jingsu Lin ◽  
M. Karimi ◽  
P. A. Dowben ◽  
G. Vidali
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Three Dimensional Structure ◽  
Ordered Phases
Sign in / Sign up

Export Citation Format

Share Document