Fractionalization on the Surface: Is Type-II Terminated $1T$-TaS${}_2$ Surface an Anomalously Realized Spin Liquid?

Abstract

The type-II terminated $1T$-TaS${}_2$ surface of a three-dimensional $1T$-TaS${}_2$ bulk material realizes the effective spin-$1/2$ degree of freedom on each David star cluster with ${\mathcal{T}}^2=-1$ such that the time-reversal symmetry is realized anomalously, despite the fact that bulk three-dimensional $1T$-TaS${}_2$ material has an even number of electrons per unit cell with ${\mathcal{T}}^2=+1$. This surface is effectively viewed as a spin-$1/2$ triangular lattice magnet, except with a fully gapped topological bulk. We further propose this surface termination realizes a spinon Fermi surface spin liquid with the surface fractionalization but with a nonexotic three-dimensional bulk. We analyze possible experimental consequences, especially the surface spectroscopic measurements, of the type-II terminated surface spin liquid.

Main text: 7 pages + 4 figures; Supplemental Material: 14 pages + 7 figures, including calculation details and more discussions

References in corpus (12)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Physics of three dimensional bosonic topological insulators: Surface Deconfined Criticality and Quantized Magnetoelectric Effect
• A classification of symmetry enriched topological phases with exactly solvable models
• Classifying fractionalization: symmetry classification of gapped Z2 spin liquids in two dimensions
• Theory of a continuous Mott transition in two dimensions
• Band insulator to Mott insulator transition in 1T-TaS${}_2$
• Unconventional Surface Critical Behaviors Induced by Quantum Phase Transition from Two-Dimensional Affleck-Kennedy-Lieb-Tasaki Phase to Néel Order
• Inducing and tuning Kondo screening in a narrow-electronic-band system
• Space group symmetry fractionalization in a family of exactly solvable models with Z2 topological order
• Stacking effect and Coulomb correlation in layered charge density wave phase of 1T-NbS2
• Low-energy behavior of spin-liquid electron spectral functions

Cited by in corpus (5)

• Thermal Hall effects in quantum magnets
• Experimental signatures of quantum and topological states in frustrated magnetism
• Is spontaneous vortex generation in superconducting 4Hb-TaS${}_2$ from vison-vortex nucleation with ${\mathbb{Z}}_2$ topological order?
• Topical review: the nature of the ground state and possibility of a quantum spin liquid in 1T metal dichalcogenides
• Phase diagram of the J1-J2 Heisenberg second-order topological quantum magnet