Far-infrared magnetospectroscopy on $\mathrm{InAs}/{\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{Sb}$ quantum-well structures has revealed new transitions ($X$ lines) when sufficient holes (in ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{Sb}$) coexist with electrons InAs) and the magnetic field is high enough. The electron-related $X$ line about 3 meV above electron cyclotron resonance, roughly same slope vs field, increases in intensity increasing hole density or...

Far-infrared magnetotransmission and photoconductivity measurements combined with visible-light, photon-dose experiments on wide-barrier GaAs/${\mathrm{Al}}_{0.3}$${\mathrm{Ga}}_{0.7}$As multiple-quantum-well samples planar doped Si donors in both well barrier centers have provided unambiguous evidence for the existence of ${\mathit{D}}^{\mathrm{\ensuremath{-}}}$ ion states evolution occupancy donor-ion electronic quantum wells excess electrons this quasi-2D system.

This paper enriches the topological horseshoe theory using finite subshift in symbolic dynamical systems, and develops an elementary framework addressing incomplete crossing semi-horseshoes. Two illustrative examples are provided: one from perturbed Duffing system another a polynomial proposed by Chen, demonstrating prevalence of semi-horseshoes chaotic systems. Moreover, semi-topological enhances detection chaos improves accuracy entropy estimation.

Far-infrared magneto-optical spectra of shallow donors confined in GaAs quantum wells the presence a quasi-two-dimensional electron gas show characteristic transition whose frequency increases with increasing density excess electrons, and slope exhibits discontinuities versus magnetic field at integer Landau level filling factors. These results demonstrate importance electron-electron interactions possibly dynamical screening high fields.

We present results of a detailed far-infrared magneto-optical study on series high-mobility InAs/${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ Sb (x=1.0, 0.8, 0.5, 0.4, 0.2, and 0.1) type-II single quantum wells. A wide range phenomena arising from the unusual properties two-dimensional (2D) electrons holes their Coulomb interaction in high magnetic fields has been revealed. Semiconducting samples (x\ensuremath{\geqslant}0.4), which only 2D exist InAs...

Low-temperature experimental measurements and variational calculations of the transition energies shallow donor (Si) impurities in bulk GaAs as a function magnetic field throughout resonant po- laron region are reported. Far-infrared photoconductivity spectra fields up to 23.5 T show several anti-level-crossing processes at above LO-phonon energy, clearly demonstrating interactions between LO phonons impurity-bound electrons involving excited impurity states. Very good agreement is obtained...

Pronounced oscillations have been observed in linewidth, amplitude, and mass of electron cyclotron resonance InAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$Sb quantum wells when holes coexist with electrons. The strength the increases sensitively electron-hole pair density; are absent for semiconducting samples (x\ensuremath{\gtrsim}0.3) which there no holes. Results interpreted terms a filling-factor-dependent interaction.

Far-infrared magnetotransmission spectroscopy has been employed to study p-type modulation-doped strained Si1−xGex/Si quantum wells grown by atmospheric pressure chemical vapor deposition at magnetic fields up 23 T. The cyclotron resonance (CR) mass of the two-dimensional hole gas (2DHG) in a 7.5 nm Si0.63Ge0.37 well was determined be (0.29±0.02)m0 for 2D density 2.3×1012/cm2 3 K. CR 2DHGs Si1−xGex is comparable previous measurements InyGa1−yAs with similar densities.

The resonant magneto-optical transitions in ${\mathit{D}}^{\mathrm{\ensuremath{-}}}$ centers GaAs/${\mathrm{Ga}}_{\mathit{x}}$${\mathrm{Al}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As quantum wells a high magnetic field are studied using the confined and interface phonon model for electron-phonon interaction. Excellent agreement with experimental results is found. Enhanced polaron effects found source of this enhancement identified as being due to statistical correlations between electrons. We...

Deep Neural Networks (DNNs) have been successfully applied to investigations of numerical dynamics finite-dimensional nonlinear systems such as ODEs instead finding solutions via the traditional Runge–Kutta method and its variants. To show advantages DNNs, in this paper, we demonstrate that DNNs are more efficient topological horseshoes chaotic dynamical systems.

We have observed the population of second two-dimensional electron subband in δ-doped Al0.48In0.52As/Ga0.47In0.53As heterostructures by Shubnikov–de Haas measurements. After illuminating samples at low temperature, density increases from 17.3 to 18.2×1011 cm−2 for first and 3.6 4.1×1011 subband. The begins when is filled a 10.3×1011 cm−2. effective mass equal (0.045±0.003)m0, indicating significant band nonparabolicity Ga0.47In0.53As well.

A systematic experimental study of confinement effects on the strength electron--optical-phonon interactions is presented. The hydrogenic 1s-2${\mathit{p}}_{+1}$ transition shallow donors in bulk GaAs and GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As multiple quantum wells (MQW) superlattices has been tuned through resonances with optical phonons by magnetic fields up to 23.5 T followed far-infrared photoconductivity spectroscopy. Extremely large...

Quasi-two-dimensional hydrogenic impurity levels in quantum wells under the influence of magnetic fields are investigated. Experimentally, 1s to np (n=2, 3, 4) transition energies various widths measured by photoconductivity technique for up 9 T. Theoretically, these calculated a new variational method that is valid whole range field strengths, from zero-field limit high-field limit. Good agreement achieved every well approximately 300 AA, which confinement effect appreciable. Consistent...

Highly excited energy levels of a hydrogenic impurity atom confined in quantum well are calculated variationally as functions magnetic fields applied the direction growth. The trial wave constructed on basis parity and nodal surface conservation, behave correctly both low-field high-field limits. With only two variational parameters for each state, all associated with different subbands can, principle, be obtained whole range magnetic-field strengths. Transition energies 1s-np (n=2,3,4)...

The Ge-composition dependence of cyclotron effective mass quasi-two-dimensional holes in strained Si1−xGex/Si quantum well structures has been investigated by far-infrared magneto-optical spectroscopy at low temperatures and high magnetic fields up to 23 T. in-plane determined from resonance energies is much less than that unstrained Si1−xGex alloys decreases systematically 0.40me 0.29me as the Ge composition increases x=0.13 x=0.37, indicating importance strain effect on valence-band...

We observed the carrier-concentration dependence of magnetic-field-induced free electron and hole recombination in semimetallic ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$Sb/InAs quantum wells. The electrons holes recombined when highest-hole Landau level crossed Fermi level. continued with increasing field until all vanished, leading to a semimetal-to-semiconductor transition. This transition shifted higher concentration decreased.

We have studied the electronic properties of ${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$Sb/InAs quantum wells, including negative persistent photoconductivity effect, magnetic-field-induced semimetal-to-semiconductor transition, and sources electron accumulation. also demonstrated that effect observed in these wells can be used as a tool to investigate not only electron-density dependence transition but alloy ionized deep donors...

Far-infrared magneto-optical spectroscopy has been used to investigate the negative persistent photoconductivity (NPPC) effect in InAs/Al0.5Ga0.5Sb quantum wells at low temperatures. After an situ cross-gap illumination, electron density InAs well is reduced by about 28%, and cyclotron effective mass decreases from (0.0342±0.0002)m0 (0.0322±0.0002)m0. The time scale for NPPC buildup transient determined results of a photon-dose experiment on order 10 ms with illumination power flux ∼10 mW/cm2.

Abstract Far infrared magneto-spectroscopic studies of quasi-2D D− ions have been carried out in several GaAs Al 0.3 Ga 0.7 As MQW samples with a wide range controlled doping the barrier constant sheet well. Temperature, carrier density dependence, and polarization new confinement-related feature on low frequency side cyclotron resonance indicate that this is likely due to triplet transition. The temperature dependence relative absorption strength D−, D0 CR were also studied found be...

In this paper, we explore the rich dynamics in Chen system using Runge–Kutta method and Deep Neural Networks (DNNs). Compared with Lorenz system, find that first return map [Formula: see text] of exhibits a more complex structure continuous regions Poincaré section. Moreover, existence six crossing blocks respect to second implies there is closed invariant set section such semi-conjugate 6-shift map, thus demonstrating remarkably chaos system.

Abstract The electronic properties of two-electron shallow impurities (D- centers) in GaAs/AlGaAs multiple-quantum-well structures have been studied via far-infrared magneto-spectroscopy. Several experimental results are reported: the electron occupation donor states at low temperature, temperature dependence occupancy, many-electron effects and resonant polaron interactions. Comparison with neutral (D0) is made.

We have studied the lowest two subbands of two-dimensional electron gas in δ-doped AlInAs/GaInAs quantum wells by Shubnikov–de Haas, Hall effect, and cyclotron resonance measurements. The effective masses determined field-dependent measurements are 0.0576m0 0.0483m0 at densities 17.3 3.6×1011 cm−2 for first second subbands, respectively. It was found that subband has heavier mass shorter lifetime than subband. Using band gap 810 meV band-edge 0.042m0 Ga0.47In0.53As, we calculated average...

Impurity bound magneto-polarons are studied experimentally and theoretically in a strongly-coupled GaAs/AlGaAs superlattice. The 1s→2p+ transition of well-center donors is tuned through resonance with the GaAs optical phonon mode. An anti-level crossing behavior three different peaks clearly observed at LO-phonon energy. theoretical analysis shows that size magneto-polaron effects: (1) very close to those for bulk system, (2) no direct evidence found non interaction.