Radiation-induced resistance oscillations in 2D electron systems with strong Rashba coupling

Physica Status Solidi (b)

2019

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This article presents a theoretical study on the experimental observation of two different kinds of beating patterns in the microwave-induced resistance oscillations at very low magnetic field in a high mobility two-dimensional electron system. In the first pattern there was no phase reversal through the beat, however, the latter experiments present a clear phase reversal of π. Based on a model that considers that the beating pattern is produced as a result of the coupling between a system of electron Landau states harmonically driven by radiation and an acoustic phonon mode, the contradictory results are explained through a different intensity coupling in terms of amplitude. In the scenario of the non-phase-reversal case, the dependence on radiation frequency and temperature is studied as well as the possibility of observation of more than one beat by lowering temperature and microwave power. It is concluded that both results can be explained with the same theoretical model that in turn is based on the microwave-driven electron orbit model that was previously developed to explain microwave-induced resistance oscillations.however the latter [33] presents a phase reversal of π. In this article we try to explain this apparent contradictory behavior based on

“…With the expression of X ( t ) (Equation ) and according to the radiation‐driven electron orbit model, we obtain for the average distance advanced by the electron in a scattering event

\begin{array}{c} center & Δ X (t) = Δ X_{0} - e^{- \frac{γ}{2} τ} A [\sin ω_{+} τ + \sin ω_{-} τ] \\ center & = Δ X_{0} - 2 A e^{- \frac{γ}{2} τ} \sin ω τ \cos normalλ τ \end{array}

where we have used the well‐known expression:

\sin true(θ_{1} true) + \sin true(θ_{2} true) = 2 \sin true[\frac{θ_{1} + θ_{2}}{2} true] \cos true[\frac{θ_{1} - θ_{2}}{2} true]

and we have considered that

A ≃ B

and that

ω_{\pm} ≃ ω \pm λ

. The time,

τ

, according to the radiation driven electron orbit model, is the “flight time,” the time it takes the electron to jump due to scattering from one orbit to another and its value is given by

τ = \frac{2 π}{ω_{c}}

. Finally and following the radiation‐driven electron orbit model we end up with an expression for R xx :

R_{x x} \propto Δ X_{0} - 2 A e^{- π \frac{γ}{w_{c}}} \sin true(2 π \frac{ω}{ω_{c}} true) \cos true(2

…”

Section: Theoretical Modelmentioning

confidence: 99%

“…The time,

τ

, according to the radiation driven electron orbit model, is the “flight time,” the time it takes the electron to jump due to scattering from one orbit to another and its value is given by

τ = \frac{2 π}{ω_{c}}

. Finally and following the radiation‐driven electron orbit model we end up with an expression for R xx :

R_{x x} \propto Δ X_{0} - 2 A e^{- π \frac{γ}{w_{c}}} \sin true(2 π \frac{ω}{ω_{c}} true) \cos true(2 π \frac{λ}{ω_{c}} true)

…”

Section: Theoretical Modelmentioning

confidence: 99%

Plasmon–Phonon Coupling in Radiation‐Induced Resistance Oscillations: Beating Pattern and Phase Reversal

Physica Status Solidi (b)

2019

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“…The phase difference α can be left out with the appropriate time shift (all driven-LS are oscillating in phase). And the total electronic orbit center coordinate in the x-direction, X ( t ), changes according to our model by 29 …”

Section: Theoretical Modelmentioning

confidence: 99%

“…Following the radiation-driven electron orbit model we can obtain the advanced distance by the electron due to charged impurity scattering when jumping between irradiated LS 29 :where Δ X (0) is the shift of the guiding center coordinate for the eigenstates involved in the scattering event when there is no light. According to the radiation-driven electron orbit model, the time is the flight time or the time it takes the electron to jump from a Landau state to another one due to scattering.…”

Section: Theoretical Modelmentioning

confidence: 99%

“…The available experimental evidence proves that these oscillations present some features that can be considered universal: they are periodic in B −1 , present a 1/4 cycle phase shift in the oscillations minima 3 , are sensitive to temperature (T) 4,5 , present a non-linear increase with the radiation power ( P ) (squared root dependence) 6–16 , are immune to the sense of circular polarization in the incident radiation 17 , and other intriguing phenomena. Different theoretical models have been presented to try to explain the origin of these effects and their features 18–29 . Yet, after more than a decade of their discovery, they are still under debate and there is no clear consensus about their physical origin.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microscopic model for radiation-induced magnetoresistance oscillations excited by circularly polarized radiation

2019

Sci Rep

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We develop a microscopic model to explain the striking result of immunity to the sense of circularly polarized radiation of the photo-excited resistance oscillations in high-mobility 2D electron systems. Our model is based on the radiation-driven electron orbit model, previously developed to explain the photo-induced resistance oscillations and zero resistance states in these systems. According to it, the guiding center of the Landau states when irradiated by circularly polarized radiation performs a circular path driven by radiation. In principle, in an infinite sample, this path is different according to the the sense of circular polarization (left or right). However, the limited size of the sample with the essential role of the edges and the concurrent presence of the Hall electric field tend to quench the displacement of the driven guiding center making nearly equal both trajectories. In the end and in the presence of scattering, the longitudinal irradiated magnetoresistance turns out nearly the same irrespective of the sense of circular radiation.

Terahertz‐Induced Oscillations in Encapsulated Graphene

Physica Status Solidi (b)

Platero

2022

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A theoretical study on the rise of photo‐oscillations in the magnetoresistance of hexagonal boron nitride (hBN)‐encapsulated graphene is presented. The previous radiation‐driven electron orbit model devised to study the same oscillations, well‐known as MIRO, in 2D semiconductor systems (GaAs/AlGaAS heterostructure) is used. It is obtained that these graphene platforms under radiation and a static magnetic field are sensitive to terahertz and far‐infrared radiation. The power, temperature, and frequency dependences of the photo‐oscillations are studied. For power dependence, it is predicted that for cleaner graphene and high enough power it is possible to observe zero‐resistance states and a resonance peak.