Coherent control over three-dimensional spin polarization for the spin-orbit coupled surface state of Bi${}_2$Se${}_3$

Abstract

Interference of spin-up and spin-down eigenstates depicts spin rotation of electrons, which is a fundamental concept of quantum mechanics and accepts technological challenges for the electrical spin manipulation. Here, we visualize this coherent spin physics through laser spin- and angle-resolved photoemission spectroscopy on a spin-orbital entangled surface-state of a topological insulator. It is unambiguously revealed that the linearly polarized laser can simultaneously excite spin-up and spin-down states and these quantum spin-basis are coherently superposed in photoelectron states. The superposition and the resulting spin rotation is arbitrary manipulated by the direction of the laser field. Moreover, the full observation of the spin rotation displays the phase of the quantum states. This presents a new facet of laser-photoemission technique for investigation of quantum spin physics opening new possibilities in the field of quantum spintronic applications.

References in corpus (5)

• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Coherent control of a single electron spin with electric fields
• Direct Measurement of the Out-of-Plane Spin Texture in the Dirac Cone Surface State of a Topological Insulator
• Spin Polarization of Photoelectrons from Topological Insulators
• Hybrid solid state qubits: the powerful role of electron spins

Cited by in corpus (2)

• Ultrafast Energy- and Momentum-resolved Surface Dirac Photocurrents in the Topological Insulator Sb${}_2$Te${}_3$
• Direct Mapping of Spin and Orbital Entangled Wavefunction under Interband Spin-Orbit coupling of Rashba Spin-Split Surface States