Obstructed insulators and flat bands in topological phase-change materials

Abstract

Phase-change materials are ubiquitous in technology because of their ability to transition between amorphous and crystalline phases fast and reversibly, upon shining light or passing a current. Here we argue that to fully understand their electronic properties it is necessary to define a novel electronic phase: the amorphous obstructed insulator. It differs from an obstructed insulator crystal in that it presents localized edge or surface states irrespective of the sample termination. Consequently, we show that obstructed amorphous insulators in three-dimensions host a surface two-dimensional flat band, detectable using ARPES. Our work establishes basic models for materials where topological and obstructed properties can be switched on and off externally, including two-dimensional surface flatbands.

7 pages + 6 pages of supplementary material and 6 figures

References in corpus (4)

• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Topological-Metal to Band-Insulator Transition in (Bi1-xInx)2Se3 Thin Films
• Bulk-boundary correspondence from the inter-cellular Zak phase

Cited by in corpus (11)

• Higher-order topological phases in crystalline and non-crystalline systems: a review
• Noncrystalline topological superconductors
• Physical properties of an Aperiodic monotile: Graphene-like features, chirality and zero-modes
• Structural spillage: an efficient method to identify non-crystalline topological materials
• Establishing Coherent Momentum-Space Electronic States in Locally Ordered Materials
• A tale of two localizations: coexistence of flat bands and Anderson localization in a photonics-inspired amorphous system
• Topological zero-modes of the spectral localizer of trivial metals
• Family of Aperiodic Tilings with Tunable Quantum Geometric Tensor
• Topological band insulators without translational symmetry
• Topological Dislocation Response in Elementary Semiconductors
• Non-self-averaging topological Anderson insulator