Electric field modulated topological magnetoelectric effect in Bi${}_2$Se${}_3$

Abstract

Topological insulators have been predicted to exhibit a variety of interesting phenomena including a quantized magnetoelectric response and novel spintronics effects due to spin textures on their surfaces. However, experimental observation of these phenomena has proved difficult due to the finite bulk carrier density which may overwhelm the intrinsic topological responses that are expressed at the surface. Here, we demonstrate a novel ionic gel gating technique to tune the chemical potential of Bi${}_2$Se${}_3$ thin films while simultaneously performing THz spectroscopy. We can tune the carrier concentration by an order of magnitude and shift the Fermi energy, E${}_F$ to as low as $\simeq$ 10 meV above the Dirac point. At high bias voltage and magnetic field, we observe a quantized Faraday angle consistent with the topological magnetoelectric effect that can be tuned by ionic gel gating through a number of plateau states

References in corpus (18)

• Topological Insulators
• Topological insulators and superconductors
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Topological Field Theory of Time-Reversal Invariant Insulators
• First observation of Spin-Momentum Helical Locking in Bi2Se3 and Bi2Te3, demonstration of Topological-Order at 300K and a realization of topological-transport-regime
• Seeing the magnetic monopole through the mirror of topological surface states
• Magnetoelectric polarizability and axion electrodynamics in crystalline insulators
• Three-Dimensional Topological Insulators
• Giant Magneto-optical Kerr Effect and Universal Faraday Effect in Thin-film Topological Insulators
• Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator
• THz response and colossal Kerr rotation from the surface states of the topological insulator Bi${}_2$Se${}_3$
• Observation of the universal magnetoelectric effect in a 3D topological insulator
• Record Surface State Mobility and Quantum Hall Effect in Topological Insulator Thin Films via Interface Engineering
• Polarization modulation time-domain terahertz polarimetry
• High-Resolution Faraday Rotation and Electron-Phonon Coupling in Surface States of the Bulk-Insulating Topological Insulator Cu${}_{0.02}$Bi${}_2$Se${}_3$
• Terahertz Kerr and Reflectivity Measurements on the Topological Insulator Bi2Se3
• A Modified $8f$ Geometry With Reduced Optical Aberrations For Improved Time Domain Terahertz Spectroscopy
• Measurement of the topological surface state optical conductance in bulk-insulating Sn-doped Bi${}_{1.1}$Sb${}_{0.9}$Te${}_2$S single crystals

Cited by in corpus (4)

• Topological magneto-optical effects and their quantization in noncoplanar antiferromagnets
• On the matter of topological insulators as magnetoelectrics
• Ambipolar magneto-optical response of ultra-low carrier density topological insulators
• From classical to quantum regime of topological surface states via defect engineering