Mapping the effect of defect-induced strain disorder on the Dirac states of topological insulators

Abstract

We provide a detailed microscopic characterization of the influence of defects-induced disorder onto the Dirac spectrum of three dimensional topological insulators. By spatially resolved Landau-levels spectroscopy measurements, we reveal the existence of nanoscale fluctuations of both the Dirac point energy as well as of the Dirac-fermions velocity which is found to spatially change in opposite direction for electrons and holes, respectively. These results evidence a scenario which goes beyond the existing picture based on chemical potential fluctuations. The findings are consistently explained by considering the microscopic effects of local stain introduced by defects, which our model calculations show to effectively couple to topological states, reshaping their Dirac-like dispersion over a large energy range. In particular, our results indicate that the presence of microscopic spatially varying stain, inevitably present in crystals because of the random distribution of defects, effectively couple to topological states and should be carefully considered for correctly describing the effects of disorder.

References in corpus (21)

• Topological Insulators
• Topological insulators and superconductors
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Crossover of Three-Dimensional Topological Insulator of Bi2Se3 to the Two-Dimensional Limit
• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• Dirac cones reshaped by interaction effects in suspended graphene
• Experimental demonstration of the topological surface states protected by the time-reversal symmetry
• Non-Fermi liquid behaviour of electrons in the half-filled honeycomb lattice (A renormalization group approach)
• Scanning Tunneling Spectroscopy of Graphene on Graphite
• Landau Quantization of Massless Dirac Fermions in Topological Insulator
• Spatial Fluctuations of Helical Dirac Fermions on the Surface of Topological Insulators
• Observation of Dirac node formation and mass acquisition in a topological crystalline insulator
• Landau quantization and the thickness limit of topological insulator thin films of Sb2Te3
• Fermi Level Tuning of Epitaxial Sb2Te3 Thin Films on Graphene by Regulating Intrinsic Defects and Substrate Transfer Doping
• Generalized effective hamiltonian for graphene under non-uniform strain
• Probing two topological surface bands of Sb2Te3 by spin-polarized photoemission spectroscopy
• Signatures of Dirac fermion-mediated magnetic order
• Experimental realization of a topological p-n junction by intrinsic defect-grading
• Detecting giant electron-hole asymmetry in graphene monolayer generated by strain and charged-defect scattering via Landau level spectroscopy
• Spatially resolved Landau level spectroscopy of the topological Dirac cone of bulk-type Sb2Te3(0001): potential fluctuations and quasiparticle lifetime
• Scattering properties of the three-dimensional topological insulator Sb2Te3: Coexistence of topologically trivial and non-trivial surface states with opposite spin-momentum helicity

Cited by in corpus (8)

• Electronic and optical properties of strained graphene and other strained 2D materials: a review
• Thermal transport, geometry, and anomalies
• Raise and collapse of strain-induced pseudo-Landau levels in graphene
• Effective magnetic field induced by inhomogeneous Fermi velocity in strained honeycomb structures
• Fingerprints of a position-dependent Fermi velocity on scanning tunnelling spectra of strained graphene
• A Systematic Investigation of the Coupling between One-Dimensional Edge States of a Topological Crystalline Insulator
• Characterizing the chemical potential disorder in the topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ thin films
• Selective-Area Epitaxy of Bulk-Insulating (Bi${}_x$Sb${}_{1-x}$)${}_2$Te${}_3$ Films and Nanowires by Molecular Beam Epitaxy