Driving ultrafast spin and energy modulation in quantum well states via photo-induced electric fields

Ciocys, Samuel; Maksimovic, Nikola; Analytis, James; Lanzara, Alessandra

doi:10.1038/s41535-022-00490-2

Cited by 5 publications

(2 citation statements)

References 75 publications

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“…Photodoping is a particularly effective tool to manipulate the electronic properties of a material via screening compared to doping with external carriers in equilibrium, as the optical excitation leads to the quasi-instantaneous creation of hot electrons and holes simultaneously. The photoinduced renormalization of bandgap or many-body interactions has been reported in, among others, semiconductors ( 10 , 11 ), superconductors ( 12 – 14 ), and topological insulators ( 15 ). In extreme cases, such abrupt changes can drive materials into nonequilibrium phases that cannot be obtained under equilibrium conditions ( 16 – 20 ).…”

Section: Introductionmentioning

confidence: 99%

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe ₂

Huber,

Lin,

Marini

et al. 2024

Sci. Adv.

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Screening, a ubiquitous phenomenon associated with the shielding of electric fields by surrounding charges, has been widely adopted as a means to modify a material’s properties. While most studies have relied on static changes of screening through doping or gating thus far, here we demonstrate that screening can also drive the onset of distinct quantum states on the ultrafast timescale. By using time- and angle-resolved photoemission spectroscopy, we show that intense optical excitation can drive 1T-TiSe 2 , a prototypical charge density wave material, almost instantly from a gapped into a semimetallic state. By systematically comparing changes in band structure over time and excitation strength with theoretical calculations, we find that the appearance of this state is likely caused by a dramatic reduction of the screening length. In summary, this work showcases how optical excitation enables the screening-driven design of a nonequilibrium semimetallic phase in TiSe 2 , possibly providing a general pathway into highly screened phases in other strongly correlated materials.

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Section: Introductionmentioning

confidence: 99%

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe ₂

Huber,

Lin,

Marini

et al. 2024

Sci. Adv.

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“…Quantum wells (QW) formed in external electric fields have diverse applications from spintronics [1] to twodimensional superconductivity [2]. QW of III-V semiconductor has a linear or triangular potential profile and is known to show interesting optical properties [3].…”

Section: Introductionmentioning

confidence: 99%

Analytical estimation of lifetime of quasi-bound states in iii-v semiconductors quantum well

Nimje,

Mahajan

2023

Phys. Scr.

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The lifetime of electrons in the Quasi Bound States in a quantum well formed by III-V semiconductors has been calculated numerically by several researchers in the past. In this work, we obtain an analytical expression for the lifetime by finding the poles of the scattering matrix in small-width approximation. Airy functions which are solutions of the Schrödinger equation for triangular potentials are expanded asymptotically for large arguments and in power series for small arguments. A scattering problem for the triangular potential well is solved with the help of mixed boundary conditions to derive the expression for the decay width that further gives the net tunneling current from the quantum well. Heterostructures of III-V materials are modeled with triangular wells whose experimental measurements are in close approximation with the theoretical calculations presented in this paper. The analytically calculated decay width in this work is also compared with the reported values by different numerical methods and found in close agreement with them.

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Ultrafast enhancement of electron-phonon coupling via dynamic quantum well states

Ciocys

Lanzara

2023

Commun Mater

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The density of states at the Fermi surface controls many material properties by influencing the low-energy interactions of conductive electrons. Typically, external tuning knobs generate only small perturbations to the density of states in crystals, since their band structure depends strongly on the lattice potential. In contrast, quantum well states are contingent on a localized potential extrinsic to the crystal lattice and can be easily modified leading to changes in the density of states at the Fermi level. Here, we are able to control the quantum well potential on the surface of Bi2Se3 with light, driving a density of states singularity below EF at ultrafast timescales, thereby triggering a reversible Lifshitz transition. We reveal a substantial ultrafast enhancement of the electron-phonon coupling with repercussions on the relaxation dynamics in the system. We argue that the relaxation dynamics are governed largely by the interplay of the dynamic density of states of the quantum wells with c-axis scattering from the $${A}_{{{{{{{{\rm{1g}}}}}}}}}^{2}$$ A 1g 2 optical phonon mode. These results demonstrate a powerful way to enhance electron-boson interaction on ultrafast timescales providing new avenues for controlling material properties and driving novel quantum phases of matter.

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Driving ultrafast spin and energy modulation in quantum well states via photo-induced electric fields

Cited by 5 publications

References 75 publications

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe ₂

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe ₂

Analytical estimation of lifetime of quasi-bound states in iii-v semiconductors quantum well

Ultrafast enhancement of electron-phonon coupling via dynamic quantum well states

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Driving ultrafast spin and energy modulation in quantum well states via photo-induced electric fields

Cited by 5 publications

References 75 publications

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe 2

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe 2

Analytical estimation of lifetime of quasi-bound states in iii-v semiconductors quantum well

Ultrafast enhancement of electron-phonon coupling via dynamic quantum well states

Contact Info

Product

Resources

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Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe ₂

Ultrafast creation of a light-induced semimetallic state in strongly excited 1T-TiSe ₂