Layer-by-layer disentanglement of Bloch states via frequency-domain photoemission

Abstract

Layer-by-layer material engineering has enabled exotic quantum phenomena such as interfacial superconductivity and the quantum anomalous Hall effect. Meanwhile, deciphering electronic states layer-by-layer remains a fundamental scientific challenge. This is exemplified by the difficulty in understanding the layer origins of topological electronic states in magnetic topological insulators, which is key to understanding and controlling topological quantum phases. Here, we report a layer-encoded frequency-domain ARPES experiment on a magnetic topological insulator (MnBi2Te4)(Bi2Te3) to characterize the layer origins of electronic states. Infrared laser excitations launch coherent lattice vibrations with the layer index encoded by the vibration frequency; photoemission spectroscopy tracks the electron dynamics, where the layer information is decoded in the frequency domain. This layer-frequency correspondence reveals a surprising wavefunction relocation of the topological surface state from the top magnetic layer into the buried second layer, reconciling the controversy over the vanishing broken-symmetry energy gap in (MnBi2Te4)(Bi2Te3) and its related compounds. The layer-frequency correspondence can be harnessed to disentangle electronic states layer-by-layer in a broad class of van der Waals superlattices.

References in corpus (10)

• Spin-orbit driven band inversion in bilayer graphene by van der Waals proximity effect
• High-temperature topological superconductivity in twisted double layer copper oxides
• Coexistence of Surface Ferromagnetism and Gapless Topological State in MnBi${}_2$Te${}_4$
• Sample-dependent Dirac point gap in MnBi${}_2$Te${}_4$ and its response to the applied surface charge: a combined photoemission and ab initio study
• Direct measurement of electron-phonon coupling with time-resolved ARPES
• Aspects of Electron-Phonon Self-Energy Revealed from Angle-Resolved Photoemission Spectroscopy
• Ferromagnetic MnBi4Te7 obtained with low concentration Sb doping: A promising platform for exploring topological quantum states
• Systemic Consequences of Disorder in Magnetically Self-Organized Topological MnBi${}_2$Te${}_4/$(Bi${}_2$Te${}_3$)${}_n$ Superlattices
• An Integrated Quantum Material Testbed with Multi-Resolution Photoemission Spectroscopy
• Direct visualization of surface spin-flip transition in MnBi4Te7

Cited by in corpus (9)

• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Dissipationless Layertronics in Axion Insulator $\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4$
• Distinguishing Surface and Bulk Electromagnetism via Their Dynamics in an Intrinsic Magnetic Topological Insulator
• Analysis methodology of coherent oscillations in time- and angle-resolved photoemission spectroscopy
• Reconstructing the wavefunction of magnetic topological insulators MnBi2Te4 and MnBi4Te7 using spin-resolved photoemission
• Preservation of Topological Surface States in Millimeter-Scale Transferred Membranes
• Spectroscopic evidence of intra-unit-cell charge redistribution in charge-neutral magnetic topological insulator Sb-doped MnBi6Te10
• Coherent Phonon-Driven Band Renormalizations in 1T${}^{\prime }$-MoTe${}_2$
• Prediction of a layer nonlinear Hall effect in bilayer nonmagnetic or antiferromagnetic systems