Transport properties of a two-dimensional electron gas dressed by light

Morina, S.; Kibis, O. V.; Pervishko, Anastasiia A.; Shelykh, I. A.

doi:10.1103/physrevb.91.155312

Cited by 75 publications

(66 citation statements)

References 44 publications

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“…However, in general it is to be expected that an oscillating vector potential would lead to coherent excited pairs with an oscillating center of mass motion, with a more substantial modification of the density of states. The change of the energy spectrum of electrons, dressed by an electromagnetic field, is, in principle, analogous to the dynamic Stark effect in atom physics [16] (and similarly for a two-dimensional electron gas [17]). Such dressed states have recently been put forward in the analysis of the microwave response of superconducting atomic point contacts [18,19].…”

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confidence: 99%

Coherent Excited States in Superconductors due to a Microwave Field

et al. 2016

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We describe theoretically the depairing effect of a microwave field on diffusive s-wave superconductors. The ground state of the superconductor is altered qualitatively in analogy to the depairing due to a dc current. In contrast to dc depairing, the density of states acquires, for microwaves with frequency ω 0 , steps at multiples of the photon energy Δ AE nℏω 0 and shows an exponential-like tail in the subgap regime. We show that this ac depairing explains the measured frequency shift of a superconducting resonator with microwave power at low temperatures. DOI: 10.1103/PhysRevLett.117.047002 How is the superconducting state modified by a current, i.e., when the condensate is moving? The answer to this question is well known for the case of a dc current flowing in a superconducting wire. For a dc current, the Cooper pairs gain a finite momentum which leads to the suppression of the superconducting properties of the wire [1,2]. The modulus of the superconducting order parameter Δ is reduced and the sharp BCS singularity near the gap is smeared. This depairing effect of a current or of a magnetic field was studied theoretically soon after the creation of the microscopic theory of superconductivity [3]. The moving superconducting condensate has been called a coherent excited state generated by the momentum displacement operator ρ q ¼ P n expðiq · r n Þ by Anderson [4] as part of the explanation of the Meissner effect from the original form of the BCS theory. The momentum displacement operator, when applied to the BCS ground state, creates excited pairs of electrons k 1 , k 2 with the momentum pairing k 1 þ k 2 ¼ q instead of zero [1,[4][5][6]. This momentum displacement q ¼ jqj corresponds to a superfluid drift velocity v s ¼ ℏq=m, where m is the electron mass. In the Green's function technique, it is possible to introduce the superfluid velocity in a gauge-invariant way, v s ∝ ½∇φ − ð2e=ℏÞA , where φ is the phase of the superconductor, e the electron charge, and A the vector potential of the electromagnetic field. The equivalence of depairing due to an electric current and due to a magnetic field is well established, both theoretically [7] and experimentally [2], using thin and narrow superconducting wires with a uniform current density. The theory of depairing by a dc current was reformulated, using the Usadel equations [8], for diffusive films with an elastic scattering length much smaller than the BCS coherence length [9]. The results of this theory [9] were confirmed experimentally by Romijn et al. However, a general theory for depairing by a microwave field, a time-dependent vector potential A, has not been formulated. In current experimental research, there are many cases in which a superconductor is used at very low temperatures, T=T c ≪ 1, where the density of quasiparticles is very low and the response of the superconductor is dominated by the response of the superfluid. At higher temperatures, it is well known that microwave radiation can be absorbed by quasiparticles, leading to a nonequilibrium di...

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Coherent Excited States in Superconductors due to a Microwave Field

et al. 2016

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“…It follows from the scattering probability (12) that the dependence arises from the Bessel function which decreases with increasing the intensity, I. Therefore, the scattering time in 2DEG, τ , increases with increasing intensity of the dressing field 15,16 . If the initial scattering time in unirradiated 2DEG, τ 0 , is large enough (the dashed line in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Such a bound electron-field system, which was called "electron dressed by field" (dressed electron), became a commonly used model in modern physics 13,14 . Recently, we demonstrated that strong interaction between 2DEG and a high-frequency electromagnetic field drastically suppresses the scattering of dressed electrons 15,16 . Since the spin relaxation depends on both the mechanism of spin-orbit interaction and scattering processes, one can expect that the spin relaxation time is strongly affected to the dressing electromagnetic field.…”

Section: Introductionmentioning

confidence: 99%

Control of spin dynamics in a two-dimensional electron gas by electromagnetic dressing

et al. 2015

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We solved the Schrödinger problem for a two-dimensional electron gas (2DEG) with the Rashba spin-orbit interaction in the presence of a strong high-frequency electromagnetic field (dressing field). The found eigenfunctions and eigenenergies of the problem are used to describe the spin dynamics of the dressed 2DEG within the formalism of the density matrix response function. Solving the equations of spin dynamics, we show that the dressing field can switch the spin relaxation in the 2DEG between the cases corresponding to the known Elliott-Yafet and D'yakonov-Perel' regimes. As a result, the spin properties of the 2DEG can be tuned by a high-frequency electromagnetic field. The present effect opens an unexplored way for controlling the spin with light and, therefore, forms the physical prerequisites for creating light-tuned spintronics devices.

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“…These electrons with substantially modified energy dispersions, referred to as "dressed states"', became a commonly used model in present-day lowdimensional physics. [36][37][38][39][40][41] One of the first significant achievements has been the demonstration of a metal-insulator transition in graphene 42 , which drastically affected the electron tunneling and the Klein paradox. 43,44 Important collective properties such as exchange and correlation energies are also affected by the presence of an energy gap, 45 and spin dynamics on the surface of a three-dimensional topological insulator 46 is also modified.…”

Section: Introductionmentioning

confidence: 99%

Exploring interacting Floquet states in black phosphorus: Anisotropy and bandgap laser tuning

Iurov

Zhemchuzhna

Gumbs

et al. 2017

Journal of Applied Physics

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The dressed states arising from the interaction between electrons and holes, and off-resonant electromagnetic radiation have been investigated for recently fabricated gapped and anisotropic black phosphorus. Our calculations were carried out for the low-energy electronic subbands near the Γ point. States for both linear and circular polarizations of the incoming radiation have been computed. However, our principal emphasis is on linearly polarized light with arbitrary polarization since this case has not been given much attention for dressing fields imposed on anisotropic structures. We have considered various cases for one-and few-layer phosphorus, including massless Dirac fermions with tunable in-plane anisotropy. Initial Hamiltonian parameters are renormalized in a largely different way compared to those for previously reported for gapped Dirac structures and, most importantly, existing anisotropy which could be modified in every direction.

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Transport properties of a two-dimensional electron gas dressed by light

Cited by 75 publications

References 44 publications

Coherent Excited States in Superconductors due to a Microwave Field

Coherent Excited States in Superconductors due to a Microwave Field

Control of spin dynamics in a two-dimensional electron gas by electromagnetic dressing

Exploring interacting Floquet states in black phosphorus: Anisotropy and bandgap laser tuning

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