Quantum Imaging of Topologically Unpaired Spin-Polarized Dirac Fermions

Abstract

The motion of a relativistic particle is linked to its spin by the Dirac equation. Remarkably, electrons in two-dimensional materials can mimic such Dirac particles but must always appear in pairs of opposite spin chirality. Using topological ideas of chiral boundary electrons wrapping a three-dimensional crystal with tuned spin-orbit coupling, we show that elusive unpaired Dirac fermions exist on the surface of a topological insulator parent matrix, pure antimony. Using scanning tunneling microscopy and angle-resolved photoemission spectroscopy we image coherent quantum interference between these particles, map their helical spin texture, and ultimately observe a transition to a single Dirac fermion distinguished by backscattering suppression via Berry phase interference. The robust dynamics of these unique spin-polarized carriers envisage future applications in spintronics and topological quantum computation.

Updated from original (copy of earlier journal submission) to include references and context to latest published and posted experiments involving STM and ARPES

References in corpus (2)

• Experimental demonstration of the topological surface states protected by the time-reversal symmetry
• STM imaging of electronic waves on the surface of Bi${}_2$Te${}_3$: topologically protected surface states and hexagonal warping effects

Cited by in corpus (9)

• Topological insulators and superconductors
• Colloquium: Topological Band Theory
• Transmission of topological surface states through surface barriers
• Dirac cone engineering in Bi${}_2$Se${}_3$ thin films
• Probing Image Potential States on Topological Semimetal Antimony Surface
• Observation of novel interference patterns in Bi2-xFexTe3+d by Fourier transform scanning tunneling spectroscopy
• Direct observation of quantum confinement of massless Dirac fermions in a topological insulator
• Kondo-effect protected topological surface states on Sb(111)
• Unconventional spin texture of a topologically nontrivial semimetal Sb(110)