Topological semimetal and Fermi-arc surface states in the electronic structure of pyrochlore iridates

By X. Wan, Ari M. Turner, Ashvin Vishwanath, S. Savrasov. 2010

1,097 citations recorded by the source corpus.

We investigate novel phases that emerge from the interplay of electron correlations and strong spin-orbit interactions. We focus on describing the topological semimetal, a three-dimensional phase of a magnetic solid, and argue that it may be realized in a class of pyrochlore iridates (such as ${\mathrm{Y}}_{2}$Ir${}_{2}$O${}_{7}$) based on calculations using the $\text{LDA}+U$ method. This state is a three-dimensional analog of graphene with linearly dispersing excitations and provides a condensed-matter realization of Weyl fermions that obeys a two-component Dirac equation. It also exhibits remarkable topological properties manifested by surface states in the form of Fermi arcs, which are impossible to realize in purely two-dimensional band structures. For intermediate correlation strengths, we find this to be the ground state of the pyrochlore iridates, coexisting with noncollinear magnetic order. A narrow window of magnetic ``axion'' insulator may also be present. An applied magnetic field is found to induce a metallic ground state.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/45ea6d9e7f77aaee5924915968a7f94f384f7f12

How researchers see this paper

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In Atomic and Molecular Physics, and Optics

1. Ashvin Vishwanath
2. Hsin Lin
3. Arun Bansil
4. Ling Lu
5. Tanmoy Das
6. Liang Fu
7. X. Dai
8. Chen Fang

In Condensed Matter Physics

1. Hsin Lin
2. Arun Bansil
3. Liang Fu
4. X. Dai
5. H. Weng
6. Z. Fang
7. Chen Fang
8. Tanmoy Das

Citations in the corpus

• Kitaev materials (2017, background): “On the theoretical side, topology is found to play a crucial role in these systems – an observation which, in the weakly correlated regime, has lead to the discovery of the topological band insulator [2, 3] and subsequently its metallic cousin, the Weyl semi-metal [4, 5].”
• Notes on Anomaly Induced Transport (2016, background): “The electronics of a new class of materials known as Dirac- and Weyl (semi-) metals [57, 18, 58] (or more generally topological metals) is governed by the Weyl equation.”
• Observation of Weyl nodes in TaAs (2015, background): “Compared with other proposals [6, 7, 12-22] in realizing a Weyl state, the TaAs family is featured by an easy sample fabrication, a non-magnetic state and no fine-tuning of the electronic states is necessary, making experimental studies of Weyl semimetals possible.”
• Flat bands, strange metals and the Kondo effect (2023, neutral): “We also describe various experimental methods to quantify the correlation strength.”
• Topological Classification of Crystalline Insulators through Band Structure Combinatorics (2016, neutral): “A notable example is found in gapless Weyl semimetals [30], one of which has been recently identified experimentally in TaAs [31–33].”