Strain-induced two-dimensional topological crystalline insulator
arXiv:2410.06661 · doi:10.1038/s41467-025-67520-y
Abstract
Topological crystalline insulators (TCIs) host topological phases of matter protected by crystal symmetries. Topological surface states in three-dimensional TCIs have been predicted and observed in IV-VI SnTe-class semiconductors. Despite the prediction of a two-dimensional (2D) TCI characterized by two pairs of edge states inside the bulk gap, materials challenges have thus far prevented its experimental realization. Here we report the growth and characterization of bilayer SnTe on the 2-NbSe substrate by molecular beam epitaxy and scanning tunneling microscopy. We experimentally observe two anticorrelated, periodically modulated pairs of conducting edge states along the perimeters of the sample with a large band gap exceeding eV. We identify these states with a 2D TCI through first principles calculations. Finally, we probe the coupling of adjacent topological edge states and demonstrate the resulting energy shift driven by a combination of electrostatic interactions and tunneling coupling. Our work opens the door to investigations of tunable topological states in 2D TCIs, of potential impact for spintronics and nanoelectronics applications at room temperature.
References in corpus (32)
- Topological Insulators
- Topological insulators and superconductors
- Quantum Spin Hall Insulator State in HgTe Quantum Wells
- Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
- Van der Waals density functionals applied to solids
- Quantized Anomalous Hall Effect in Magnetic Topological Insulators
- Topological Crystalline Insulators
- Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
- First observation of Spin-Momentum Helical Locking in Bi2Se3 and Bi2Te3, demonstration of Topological-Order at 300K and a realization of topological-transport-regime
- Wannier90 as a community code: new features and applications
- Topological Crystalline Insulators in the SnTe Material Class
- Experimental realization of a topological crystalline insulator in SnTe
- Reflection symmetric second-order topological insulators and superconductors
- Higher-Order Topology in Bismuth
- Topological Crystalline Insulators and Topological Superconductors: From Concepts to Materials
- A topological crystalline insulator (TCI) phase via topological phase transition and crystalline mirror symmetry
- Progress and prospects in magnetic topological materials
- One-dimensional Topological Edge States of Bismuth Bilayers
- Spin-filtered Edge States with an Electrically Tunable Gap in a Two-Dimensional Topological Crystalline Insulator
- Observation of Dirac node formation and mass acquisition in a topological crystalline insulator
- Large Chern Number Quantum Anomalous Hall Effect In Thin-film Topological Crystalline Insulators
- Topological Mirror Superconductivity
- Topological Crystalline Kondo Insulator in Mixed Valence Ytterbium Borides
- Topological switch between second-order topological insulators and topological crystalline insulators
- Crystal Field Effect Induced Topological Crystalline Insulators In Monolayer IV-VI Semiconductors
- Robust spin-polarized midgap states at step edges of topological crystalline insulators
- Dirac mass generation from crystal symmetry breaking on the surfaces of topological crystalline insulators
- Mapping the unconventional orbital texture in topological crystalline insulators
- A pressure-induced topological phase with large Berry curvature in PbSnTe
- Topological Crystalline Insulator Nanomembrane with Strain-Tunable Band Gap
- A Systematic Investigation of the Coupling between One-Dimensional Edge States of a Topological Crystalline Insulator
- Control of molecular orbital ordering using a van der Waals monolayer ferroelectric