Stepwise quantized surface states and delayed Landau level hybridization in Co cluster-decorated BiSbTeSe2 topological insulator devices

Abstract

In three-dimensional topological insulators (TIs), the nontrivial topology in their electronic bands casts a gapless state on their solid surfaces, using which dissipationless TI edge devices based on the quantum anomalous Hall (QAH) effect and quantum Hall (QH) effect have been demonstrated. Practical TI devices present a pair of parallel-transport topological surface states (TSSs) on their top and bottom surfaces. However, due to the no-go theorem, the two TSSs always appear as a pair and are expected to quantize synchronously. Quantized transport of a separate Dirac channel is still desirable, but has never been observed in graphene even after intense investigation over a period of 13 years, with the potential aim of half-QHE. By depositing Co atomic clusters, we achieved stepwise quantization of the top and bottom surfaces in BiSbTeSe2 (BSTS) TI devices. Renormalization group flow diagrams13, 22 (RGFDs) reveal two sets of converging points (CVPs) in the (Gxy, Gxx) space, where the top surface travels along an anomalous quantization trajectory while the bottom surface retains 1/2 e2/h. This results from delayed Landau-level (LL) hybridization (DLLH) due to coupling between Co clusters and TSS Fermions.

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Cited by in corpus (16)

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• Half-Quantized Hall Effect and Power Law Decay of Edge Current Distribution
• Half-Quantized Hall Effect at the Parity-Invariant Fermi Surface
• Half-Quantized Helical Hinge Currents in Axion Insulators
• Altermagnetism-Induced Parity Anomaly in Weak Topological Insulators
• Phase transition and anomalous scaling in the quantum Hall transport of topological insulator Sn-Bi1.1Sb0.9Te2S devices
• Topological Phase Transition-Induced Tri-Axial Vector Magnetoresistance in (Bi1-xInx)2Se3 Nanodevices
• Signature of Parity Anomaly: Crossover from One Half to Integer Quantized Hall Conductance in a Finite Magnetic Field
• 2D-Dirac surface states and bulk gap probed via quantum capacitance in a 3D topological insulator
• Quarter-quantized thermal Hall effect with parity anomaly
• Metallic Quantized Anomalous Hall Effect without Chiral Edge States
• Quantum oscillations and nontrivial transport in (Bi0.92In0.08)2Se3
• Reversible Engineering of Topological Insulator Surface State Conductivity through Optical Excitation
• Diagnosing the magnetic field-tuned symmetry nature of the topological electrons by conductance fluctuations in bulk-insulating BiSbTeSe2 devices
• Parity Anomalous Semimetal with Minimal Conductivity Induced by an In-Plane Magnetic Field
• Prediction of at topological $p+ip$ excitonic insulator with parity anomaly