Disentangling High Harmonic Generation from Surface and Bulk States of a Topological Insulator

Li, Sha; Zhou, Wenyi; Imroz, Kazi A.; Tang, Yaguo; Townsend, Tiana A.; Leshchenko, Vyacheslav; Boie, Larissa; Agostini, Pierre; Landsman, Alexandra S.; Kawakami, Roland K.; Yue, Lun; DiMauro, Louis F.

doi:10.48550/arxiv.2604.06051

DOE OSTI · 3030120

Disentangling High Harmonic Generation from Surface and Bulk States of a Topological Insulator

Li, Sha·Zhou, Wenyi·Imroz, Kazi A.·Tang, Yaguo·Townsend, Tiana A.·Leshchenko, Vyacheslav·Boie, Larissa·Agostini, Pierre·Landsman, Alexandra S.·Kawakami, Roland K.·Yue, Lun·DiMauro, Louis F.

View original source ↗Read source document ↗Export metadata ↓

Abstract

The discovery of topological phases has introduced a new dimension to materials science. Three-dimensional (3D) topological insulators (TIs) are a remarkable class of matter that is insulating in the bulk while hosting conductive topological surface states (TSSs) with unique charge and spin properties. High-order harmonic generation (HHG) has emerged as a powerful tool to probe condensed matter systems by providing insights into their electronic structure and dynamic behavior. Here, we investigate HHG in the prototype 3D-TI Bi$_2$Se$_3$. We demonstrate that the contributions of bulk and surface states to the harmonic emission can be controlled by tuning the thickness of thin film samples. An ultrathin (6 nm) film substantially enhances HHG from the surface states, while the bulk states dominate HHG in a thicker (50 nm) film. By applying a quasi-static terahertz perturbing field, we disentangle the bulk and surface responses and reveal the significant impact of the surface states' shift vector and Berry curvature on HHG. Our study provides effective methods for isolating the optical responses of TSSs from those of the bulk, which opens the door to resolving an ongoing debate regarding whether it is possible to reliably extract topological signatures in HHG.

Explore related subjects

Atomic Physics (physics.atom-ph)FOS: Physical sciences Mesoscale and Nanoscale Physics (cond-mat.mes-hall)Optics (physics.optics)Other Condensed Matter (cond-mat.other)

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Li, Sha, Zhou, Wenyi, Imroz, Kazi A., Tang, Yaguo, Townsend, Tiana A., Leshchenko, Vyacheslav, Boie, Larissa, Agostini, Pierre, Landsman, Alexandra S., Kawakami, Roland K., Yue, Lun, DiMauro, Louis F.. 2026-01-01. Disentangling High Harmonic Generation from Surface and Bulk States of a Topological Insulator. https://doi.org/10.48550/arxiv.2604.06051

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Shake-up and shake-off spectra in the electron capture decay of atomic $^7$Be

The most stringent laboratory-based experimental limits on the existence of sub-MeV sterile neutrinos are currently set by decay spectroscopy of radioactive $^7$Be embedded into superconducting sensors. The systematic uncertainties are dominated by the modeling of the electron shake-up and shake-off spectra that are not based on state-of-the-art atomic theory and do not include electron correlations or relativistic effects. We have used the multiconfiguration Dirac-Fock formalism to obtain correlated wavefunctions ab initio and compute all single and double shake processes in the electron capture decay of atomic $^7$Be. The simulations can explain some but not all of the observed spectral features, likely because the wave functions are modified by the Ta sensor material that the $^7$Be is embedded into. The new models also show that the L/K electron capture ratio of $^7$Be in Ta has previously been slightly underestimated revising the previous value of 0.070(7) to a new value of 0.0756(20).

Atomic Physics (physics.atom-ph)↗

DOE OSTI2025

Non-invasive mid-circuit measurement and reset on atomic qubits

Mid-circuit measurement and reset of subsets of qubits is a crucial ingredient of quantum error correction and many quantum information applications. Measurement of atomic qubits is accomplished through resonant fluorescence, which typically disturbs neighboring atoms due to photon scattering. We propose and prototype a new scheme for measurement that provides both spatial and spectral isolation by using tightly-focused individual laser beams and narrow atomic transitions. The unique advantage of this scheme is that all operations are applied exclusively to the read-out qubit, with negligible disturbance to the other qubits of the same species and little overhead. In this letter, we pave the way for non-invasive and high fidelity mid-circuit measurement and demonstrate all key building blocks on a single trapped barium ion.

Atomic Physics (physics.atom-ph)↗

DOE OSTI2025

In-situ mid-circuit qubit measurement and reset in a single-species trapped-ion quantum computing system

We implement in-situ mid-circuit measurement and reset (MCMR) operations on a trapped-ion quantum computing system by using metastable qubit states in $^{171}\textrm{Yb}^+$ ions. We introduce and compare two methods for isolating data qubits from measured qubits: one shelves the data qubit into the metastable state and the other drives the measured qubit to the metastable state without disturbing the other qubits. We experimentally demonstrate both methods on a crystal of two $^{171}\textrm{Yb}^+$ ions using both the $S_{1/2}$ ground state hyperfine clock qubit and the $S_{1/2}$-$D_{3/2}$ optical qubit. These MCMR methods result in errors on the data qubit of about $2\%$ without degrading the measurement fidelity. With straightforward reductions in laser noise, these errors can be suppressed to less than $0.1\%$. The demonstrated method allows MCMR to be performed in a single-species ion chain without shuttling or additional qubit-addressing optics, greatly simplifying the architecture.

Atomic Physics (physics.atom-ph)↗