A comparative study on heat capacity, magnetization and magnetic susceptibility for a GaAs quantum dot with asymmetric confinement

Castaño-Yepes, Jorge David; Ramirez-Gutierrez, C.F.; Correa-Gallego, H.; Gómez, Edgar A.

doi:10.1016/j.physe.2018.05.022

Cited by 29 publications

(13 citation statements)

References 56 publications

(47 reference statements)

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“…On the other hand, by comparison with Refs. [36] and [37], the magnetic phase diagram from Fig. 2-(b) shows the emergence of a paramagnetic phase (represented by the white region at high magnetic fields).…”

Section: Resultsmentioning

confidence: 99%

“…Finally, it is noteworthy from Fig. 4 that the param-agnetic region in the low-temperature low-external field regime typical from GaAs QDs [36,37] disappears when the out-of-equilibrium corrections are introduced using the χ 2 -SE formalism for decreasing number of subsystems N . This is physically interpreted as a lack of order in the spins coming from the fact that for small N , a low average temperature will still have important contributions from subsystems with higher local temperature that will break the order of the spins in a global description.…”

Section: Resultsmentioning

confidence: 99%

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Super-statistical description of thermo-magnetic properties of a system of 2D GaAs quantum dots with gaussian confinement and Rashba spin–orbit interaction

Castaño-Yepes

Amor-Quiroz

2020

Physica A: Statistical Mechanics and its Applications

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We examine the effect of non-equilibrium processes modeled by the introduction of a generalized Boltzmann factor on the thermal and magnetic properties of an array of two-dimensional GaAs quantum dots in the presence of an external uniform and constant magnetic field. The model consists of a single-electron subject to a confining Gaussian potential with a spin-orbit interaction in the Rashba approach. We compute the specific heat and the magnetic susceptibility within the formalism of χ 2 -superstatistics from the exact solution of the Schrödinger equation. Furthermore, an analytic solution for the partition function allows a study of the impact of the number of subsystems on the superstatistical corrections and confirms that the ordinary thermo-magnetic properties are recovered whenever the thermal distribution can be approximated by a Dirac delta. Also, we found a progressive disappearance of the Schottky anomaly with decreasing number of subsystems, while the specific heat ceases to be a monotonically increasing function with respect to the average temperature when the χ 2 -distribution is spread over a large range of temperatures. Remarkably, the introduction of fluctuations in the temperature is found to suppress the paramagnetic phase transition that would otherwise appear at low temperatures. Finally, we emphasize that an appropriate construction of the definition of physical observables is crucial for obtaining a correct description of the physics derived from a non-extensive construction of the entropy.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Super-statistical description of thermo-magnetic properties of a system of 2D GaAs quantum dots with gaussian confinement and Rashba spin–orbit interaction

Castaño-Yepes

Amor-Quiroz

2020

Physica A: Statistical Mechanics and its Applications

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“…6-(a) We use the PPM approximation without including the SOI and for p = 1. Such diagram was included for comparative purposes as it represents the case without a topolog- ical disclination which has been analyzed before [16]. In Fig.…”

Section: Resultsmentioning

confidence: 99%

Impact of a topological defect and Rashba spin-orbit interaction on the thermo-magnetic and optical properties of a 2D semiconductor quantum dot with Gaussian confinement

Castaño-Yepes

Amor-Quiroz

Ramirez-Gutierrez

et al. 2019

Physica E: Low-dimensional Systems and Nanostructures

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In this paper, we examine the effect of introducing a conical disclination on the thermal and optical properties of a two dimensional GaAs quantum dot in the presence of a uniform and constant magnetic field. In particular, our model consists of a single-electron subject to a confining Gaussian potential with a spin-orbit interaction in the Rashba approach. We compute the specific heat and the magnetic susceptibility from the exact solution of the Schrödinger equation via the canonical partition function, and it is shown that the peak structure of the Schottky anomaly is linearly displaced as a function of the topological defect. We found that such defect and the Rashba coupling modify the values of the temperature and magnetic field in which the system behaves as a paramagnetic material. Remarkably, the introduction of a conical disclination in the quantum dot relaxes the selection rules for the electronic transitions when an external electromagnetic field is applied. This creates a new set of allowed transitions causing the emergence of semi-suppressed resonances in the absorption coefficient as well as in the refractive index changes which are blue-shifted with respect to the regular transitions for a quantum dot without the defect.

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“…As RMQD confinement potential exhibits a parabolic encompassing, it agrees with a well‐like shape profile suggested by the experimental studies to encompass the electrons . If the most possible low‐dimensional structure to fabricate experimentally is considered to be QW, it is more accurate that theoretical research also focuses on well‐like shape profiles such as Gaussian, the power‐exponential, and parabolic confinements . In this manner, if the possibility of generating a quantum dot with Rosen‐Morse (RM) confinement because of developed nanofabrication technology is considered, it is clear that the results of the present study can be an important manual for device design, optimization, and generation research.…”

Section: Introductionmentioning

confidence: 90%

Magneto‐optical specifications of Rosen‐Morse quantum dot with screw dislocation

Bahar

Ungan

2020

Int J of Quantum Chemistry

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This is the first study to consider a quantum dot with screw dislocation that has Rosen-Morse (RM) confinement potential, generated by a GaAs/GaAlAs heterostructure.An external magnetic field and Aharonov-Bohm (AB) flux field were also applied on RM quantum dot (RMQD) in order to stave the effects of a screw dislocation defect. The combined effect of the screw dislocation defect, the external magnetic field, and AB flux field on the total refractive index changes (TRICs) and the total absorption coefficients (TACs) of RMQD are thus investigated. Cylindrical coordinates are used due to the direction of application of the torsion and the external fields, as well as due to the structure's symmetry. The effective mass approximation and tridiagonal matrix methods are used in order to obtain the subband energy spectra and electronic wave functions of RMQD.The nonlinear optical specifications of RMQD are checked using compact-density-matrix formalism within the framework of the iterative method. Reviews without screw dislocation are also carried out in order to be able to clarify the effects of a screw dislocation defect on the optical properties, and then, both cases are deliberated. This study is the first attempt to analyze the AB flux field for RMQD without screw dislocation. In the present study, the influences of a screw dislocation defect on RMQD's TRICs and TACs are probed by considering different values of the external magnetic field and AB flux field, and the ranges of corresponding parameters on the optimum of the structure are specified. Moreover, the study also elucidates how to rule out the effects of screw dislocation on optical specifications by means of the external fields. Despite a certain screw dislocation, the frequency range is determined where the structure behaves as if it is perfect (namely, without screw dislocation) for its optimum, which in turn is crucial for experimental applications. K E Y W O R D SAharonov-Bohm flux field, magnetic field, nonlinear optical properties, quantum dot, screw dislocation, Rosen-Morse (RM) confinement potential

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A comparative study on heat capacity, magnetization and magnetic susceptibility for a GaAs quantum dot with asymmetric confinement

Cited by 29 publications

References 56 publications

Super-statistical description of thermo-magnetic properties of a system of 2D GaAs quantum dots with gaussian confinement and Rashba spin–orbit interaction

Super-statistical description of thermo-magnetic properties of a system of 2D GaAs quantum dots with gaussian confinement and Rashba spin–orbit interaction

Impact of a topological defect and Rashba spin-orbit interaction on the thermo-magnetic and optical properties of a 2D semiconductor quantum dot with Gaussian confinement

Magneto‐optical specifications of Rosen‐Morse quantum dot with screw dislocation

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