Weyl semimetal from spontaneous inversion symmetry breaking in pyrochlore oxides

Abstract

We study the electronic properties of strongly spin-orbit coupled electrons on the elastic pyrochlore lattice. Akin to the Peierls transition in one-dimensional systems, the coupling of the lattice to the electronic degrees of freedom can stabilize a spontaneous deformation of the crystal. This deformation corresponds to a breathing mode, which breaks the inversion symmetry. We find that for intermediate values of the staggered strain, the inversion-symmetry broken phase realizes a topological Weyl semimetal. In the temperature-elasticity phase diagram, the Weyl semimetal shows a reentrant phase behavior: it can be reached from a symmetric phase realized both at higher and at lower temperatures. The symmetric phase is a Dirac semimetal, which is protected by the non-symmorphic space group of the pyrochlore lattice. Beyond a critical value of the staggered strain, the symmetry-broken phase is a fully gapped trivial insulator. The surface states of the Weyl semimetal form open Fermi arcs and we observe that their connectivity depends on the termination of the crystal. In particular, for the $\{111\}$ films, the semiclassical closed electronic orbits of the surface states in a magnetic field cross the bulk either twice, four, six or twelve times. We demonstrate how one can tune the number of bulk crossings through a Lifshitz-like transition of the Fermi arcs, which we call Weyl-Lifshitz transition, by applying a surface potential. Our results offer a route to a topological Weyl semimetal in nonmagnetic materials and might be relevant for pyrochlore oxides with heavy transition-metal ions such as alloys of iridates.

18 pages, 11 figures

References in corpus (19)

• Weyl semimetal phase in non-centrosymmetric transition metal monophosphides
• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Topological response in Weyl semimetals and the chiral anomaly
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Quantum transport evidence for a three-dimensional Dirac semimetal phase in Cd3As2
• Weyl semimetals from noncentrosymmetric topological insulators
• Friedel oscillations due to Fermi arcs in Weyl semimetals
• Universal phase diagrams for the quantum spin Hall systems
• Magnetic orders and topological phases from f-d exchange in pyrochlore iridates
• Flat bands with higher Chern number in pyrochlore slabs
• Emergent topological phenomena in thin films of pyrochlore iridates
• Pyrochlore electrons under pressure, heat and field: shedding light on the iridates
• Topology and Interactions in a Frustrated Slab: Tuning from Weyl Semimetals to C > 1 Fractional Chern Insulators
• Experimental Realization of a Quantum Breathing Pyrochlore Antiferromagnet
• Interacting Weyl semimetals: characterization via the topological Hamiltonian and its breakdown
• Metamagnetism of itinerant electrons in multi-layer ruthenates
• Topological phases in layered pyrochlore oxide thin films along the [111] direction
• Bond order wave instabilities in doped frustrated antiferromagnets: "Valence bond solids" at fractional filling
• Observation of Fermi Arc Surface States in a Topological Metal: A New Type of 2D Electron Gas beyond Z2 Topological Insulators

Cited by in corpus (2)

• Higher-order topological insulators and semimetals on the breathing Kagome and pyrochlore lattices
• Strain induced Chiral Magnetic Effect in Weyl semimetals