Universal Metallic Surface States in Electride

Abstract

Robust metallic surface states (MSS) of topological insulator (TI) against imperfections and perturbations are important in broad applications such as chemical catalysis and quantum computing. Unfortunately, they are suffered from the narrow band gap that can be accessed. Searching for MSS with large bulk band gap beyond conventional TIs becomes a quest. In this work, inspired by the adiabatic connection principle in real space, we identify that all electrides, a new class of emerging materials, must host robust and universal MSS that resists any disturbances, in spite of the fact that some of them could be classified as trivial in standard topology theory. This counterintuitive property is traced to the specific charge localization-delocalization change intrinsic to electride when approaching the crystalline surface or interface, which is a kind of interstice-centered to atom-centered transition in the real-space topology of the charge density distribution, and is sharply different from the band inversion in the standard topology theory. The new mechanism circumvents the obstacle that limits the band gap of TI. Robust and universal MSS in an electride that conventionally-determined as trivial but with a colossal band gap beyond 6.13 eV are demonstrated. This gap size is about 6-fold larger than the highest record of known "wide-gap" TIs, thus opens up new avenues to universal MSS with gigantic bulk gap.

32 pages, 7 figures, with supporting information

References in corpus (25)

• Topological insulators and superconductors
• Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Accurate and efficient algorithm for Bader charge integration
• Topological Insulator Materials
• Topological quantum chemistry
• The (High Quality) Topological Materials In The World
• Transparent dense sodium
• Bulk Band Gap and Surface State Conduction Observed in Voltage-Tuned Crystals of the Topological Insulator Bi${}_2$Se${}_3$
• Topological Semimetals Predicted from First-principles Calculations
• Line of Dirac Nodes in Hyper-Honeycomb Lattices
• All Topological Bands of All Nonmagnetic Stoichiometric Materials
• A large energy-gap oxide topological insulator based on the superconductor BaBiO3
• On the constitution of sodium at higher densities
• Topological Dirac Nodal Lines and Surface Charges in fcc Alkaline Earth Metals
• Low-Energy Effective Hamiltonian for Giant-Gap Quantum Spin Hall Insulators in Honeycomb X-Hydride/Halide (X=N-Bi) Monolayers
• The role of delocalized chemical bonding in square-net-based topological semimetals
• Metallic Icosahedron Phase of Sodium at Terapascal Pressures
• Superconductivity in Li8Au electride
• Predicted superconductivity and superionic state in the electride Li${}_5$N under high pressure
• Interplay of anionic quasi-atom and interstitial point defects in electrides: abnormal interstice occupation and colossal charge state of point defects in dense FCC-lithium
• Optical properties of dense lithium in electride phases by first-principles calculations
• Three-Dimensional Real Space Invariants, Obstructed Atomic Insulators and A New Principle for Active Catalytic Sites
• Predicted novel insulating electride compound between alkali metals lithium and sodium under high pressure
• Prediction of anomalous LA-TA splitting in electrides

Cited by in corpus (4)

• Simultaneous Superconducting and Topological Properties in Mg-Li Electrides at High Pressures
• Rational regulation strategies of interstitial localized electrons in electride: A density functional theory study
• Distinctive Electronic Characteristics and Ultra-high Thermoelectric Power Factor in Be-Fe Intermetallics
• Hyperbolic Dispersion and Low-Frequency Plasmons in Electrides