Phase invariance of the semiconductor Bloch equations

Li, Jinbin; Zhang, Xiao; Fu, Silin; Feng, Yingjie; Hu, Bitao; Du, Hongchuan

doi:10.1103/physreva.100.043404

Cited by 76 publications

(35 citation statements)

References 34 publications

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“…It is also confirmed that for the applied laser parameters, no detectable harmonic signals are produced from the bare substrate. Ultrafast Science solving the semiconductor Bloch equations (SBEs) [37],…”

Section: Methodsmentioning

confidence: 99%

Polarization Flipping of Even-Order Harmonics in Monolayer Transition-Metal Dichalcogenides

et al. 2021

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We present a systematic study of the crystal-orientation dependence of high-harmonic generation in monolayer transition-metal dichalcogenides, WS2 and MoSe2, subjected to intense linearly polarized midinfrared laser fields. The measured spectra consist of both odd- and even-order harmonics, with a high-energy cutoff extending beyond the 15th order for a laser-field strength around ~1 V/nm. In WS2, we find that the polarization direction of the odd-order harmonics smoothly follows that of the laser field irrespective of the crystal orientation, whereas the direction of the even-order harmonics is fixed by the crystal mirror planes. Furthermore, the polarization of the even-order harmonics shows a flip in the course of crystal rotation when the laser field lies between two of the crystal mirror planes. By numerically solving the semiconductor Bloch equations for a gapped-graphene model, we qualitatively reproduce these experimental features and find the polarization flipping to be associated with a significant contribution from interband polarization. In contrast, high-harmonic signals from MoSe2 exhibit deviations from the laser-field following of odd-order harmonics and crystal-mirror-plane following of even-order harmonics. We attribute these differences to the competing roles of the intraband and interband contributions, including the deflection of the electron-hole trajectories by nonparabolic crystal bands.

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Section: Methodsmentioning

confidence: 99%

Polarization Flipping of Even-Order Harmonics in Monolayer Transition-Metal Dichalcogenides

et al. 2021

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“…Important features are quantum interference effects in many-band configurations, [20,23] Berry curvature and the closely associated gaugedependent Berry connection as well as the phase of the complex valued transition dipoles. [24][25][26][27][28] Quantum interference, i.e., the nonperturbative interference of direct and indirect excitation pathways, was shown to explain the emission of parallel polarized even-order harmonics and its subcycle time structure, [20] the Berry curvature dominates the emission of perpendicular-polarized HHG and the response to very low excitation frequencies. [25][26][27] Herein, we focus on the mechanism of quantum interference and provide a theoretical analysis for the resulting intensity ratio between even and odd harmonic emission induced by strong-field THz excitation in semiconductors.…”

Section: Introductionmentioning

confidence: 99%

Probing Intervalence Band Coupling via High‐Harmonic Generation in Binary Zinc‐Blende Semiconductors

Hagen

Koch

2021

Physica Rapid Research Ltrs

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A systematic microscopic theory is presented for high‐harmonic generation in III–V semiconductors that are excited by strongly detuned high‐intensity electromagnetic pulses. As a mechanism for the appearance of even harmonic orders, the quantum interference of different transition paths is analyzed. For the binary zinc‐blende semiconductors, InAs, InP, and GaAs, the intensity ratio between even‐ and odd‐order harmonic emission depends on the strength of the respective intervalence band dipole coupling. However, the large intervalence band dipole in InP leads to even and odd harmonics of similar intensity, no or only very minor even‐order emission due to quantum interference is predicted for InAs where the fundamental transition is strongly favored over intervalence band transitions.

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“…Due to its flexibility in constructing self-consistent model systems, this methodology was applied to investigate topological edge effects [51,52] and various types of imperfection effects such as doping [53], disorder [52,54], and vacancies [55]. We note that recently such a finite-system model was also used for studying the carrier-envelope-phase effects [60], for examining the phase invariance of the SBEs [61], and for comparing semiclassical trajectory models [62]. For investigating HHG from an ideal periodic crystal lattice, however, it could be advantageous to extend the finite-system TDDFT model to the infinite periodic limit, as we will do in the present work.…”

Section: Introductionmentioning

confidence: 99%

Crystal-momentum-resolved contributions to multiple plateaus of high-order harmonic generation from band-gap materials

Iravani

Madsen

2020

Phys. Rev. A

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We study the crystal-momentum-resolved contributions to the high-order harmonic generation (HHG) in band-gap materials, and identify the relevant initial crystal momenta for the first and higher plateaus of the HHG spectra. We do so by using a time-dependent density-functional theory model of one-dimensional linear chains. We introduce a self-consistent periodic treatment for the infinitely extended limit of the linear chain model, which provides a convenient way to simulate and discuss the HHG from a perfect crystal beyond the single-active-electron approximation. The multiplateau spectral feature is elucidated by a semiclassical k-space trajectory analysis with multiple conduction bands taken into account. In the considered laser-interaction regime, the multiple plateaus beyond the first cutoff are found to stem mainly from electrons with initial crystal momenta away from the point (k = 0), while electrons with initial crystal momenta located around the point are responsible for the harmonics in the first plateau. We also show that similar findings can be obtained from calculations using a sufficiently large finite model, which proves to mimic the corresponding infinite periodic limit in terms of the band structures and the HHG spectra.

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Phase invariance of the semiconductor Bloch equations

Cited by 76 publications

References 34 publications

Polarization Flipping of Even-Order Harmonics in Monolayer Transition-Metal Dichalcogenides

Polarization Flipping of Even-Order Harmonics in Monolayer Transition-Metal Dichalcogenides

Probing Intervalence Band Coupling via High‐Harmonic Generation in Binary Zinc‐Blende Semiconductors

Crystal-momentum-resolved contributions to multiple plateaus of high-order harmonic generation from band-gap materials

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