scholarly journals Stark Shift and Field Induced Tunneling in Doped Quantum Wells with Arbitrary Potential Profiles

1996 ◽  
Vol 450 ◽  
Author(s):  
S. Panda ◽  
B. K. Panda ◽  
S. Fung ◽  
C. D. Beling
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Density Functional ◽  
Local Density ◽  
Golden Rule ◽  
Uniform Electric Field ◽  
Functional Theory ◽  
Poisson Equations ◽  
Fourier Series Method ◽  
Arbitrary Potential

ABSTRACTThe energies and resonance widths of single doped quantum wells consisting of Al-GaAs/GaAs with rectangular and annealing induced diffusion modified shapes are calculated under an uniform electric field using the stabilization method. The electronic structure is calculated without an electric field in the finite temperature density functional theory with exchange-correlation potential treated in the local density approximation. Our scheme for solving the Schrödinger and Poisson equations is based on the Fourier series method. The electric field is added to the self-consistent potential and energies are obtained as a function of the combined width of the well and barriers. This yields us the stabilization graph from which the energies and resonance widths at different field strengths are extracted using the Fermi Golden rule.

Optical properties of monolayer BeC under an external electric field: A DFT approach

2018 ◽  
Vol 3 (9) ◽  
Author(s):  
Suman Chowdhury ◽  
Debnarayan Jana
Keyword(s):  
Optical Properties ◽  
Field Strength ◽  
Electric Field ◽  
Band Gap ◽  
Density Functional ◽  
Optical Data ◽  
Uniform Electric Field ◽  
Functional Theory ◽  
Applied Electric Field Strength ◽  
Electron Energy Loss

Abstract BeC, a two-dimensional hypercoordinated nanostructure carbon compound, has been the focus of the nanoworld because of its high value of dynamical stability, in-plane stiffness, carrier mobility and the existence of band gap. In this work, we have explored the electronic and the optical properties of this material under the influence of static external perpendicular electric field within the framework of density functional theory. Under the influence of a uniform electric field, the band gap changes within the meV range. The electron energy loss function study reveals that this material has optical band gaps which remain constant irrespective of the applied electric field strength. The optical property also exhibits interesting features when the applied field strength is within 0.4–0.5 V/Å. We have also tried to explain the optical data from the respective band structures and thus paving the way to understand qualitatively the signature of the optical anisotropy from the birefringence study.

Density Functional Theory Study of Antioxidant Adsorption onto Single- Wall Boron Nitride Nanotubes: Design of New Antioxidant Delivery Systems

2019 ◽  
Vol 22 (7) ◽  
pp. 470-482
Author(s):  
Samereh Ghazanfary ◽  
Fatemeh Oroojalian ◽  
Rezvan Yazdian-Robati ◽  
Mehdi Dadmehr ◽  
Amirhossein Sahebkar
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Vitamin C ◽  
Electric Field ◽  
External Electric Field ◽  
Lipoic Acid ◽  
Density Functional ◽  
Cell Interaction ◽  
Boron Nitride Nanotubes ◽  
Functional Theory

Background: Boron Nitride Nanotubes (BNNTs) have recently emerged as an interesting field of study, because they could be used for the realization of developed, integrated and compact nanostructures to be formulated. BNNTs with similar surface morphology, alternating B and N atoms completely substitute for C atoms in a graphitic-like sheet with nearly no alterations in atomic spacing, with uniformity in dispersion in the solution, and readily applicable in biomedical applications with no obvious toxicity. Also demonstrating a good cell interaction and cell targeting. Aim and Objective: With a purpose of increasing the field of BNNT for drug delivery, a theoretical investigation of the interaction of Melatonin, Vitamin C, Glutathione and lipoic acid antioxidants using (9, 0) zigzag BNNTs is shown using density functional theory. Methods: The geometries corresponding to Melatonin, Vitamin C, Glutathione and lipoic acid and BNNT with different lengths were individually optimized with the DMOL3 program at the LDA/ DNP (fine) level of theory. Results: In the presence of external electric field Melatonin, Vitamin C, Glutathione and lipoic acid could be absorbed considerably on BNNT with lengths 22 and 29 Å, as the adsorption energy values in the presence of external electric field are considerably increased. Conclusion: The external electric field is an appropriate technique for adsorbing and storing antioxidants on BNNTs. Moreover, it is believed that applying the external electric field may be a proper method for controlling release rate of drugs.

Density Functional Theory Approach for Muon Sites Estimation in Mn3Sn

2021 ◽  
Vol 1028 ◽  
pp. 199-203
Author(s):  
Fiqhri Heda Murdaka ◽  
Edi Suprayoga ◽  
Abdul Muizz Pradipto ◽  
Kohji Nakamura ◽  
Agustinus Agung Nugroho
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Local Density ◽  
Full Potential ◽  
Theory Approach ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electrostatic Potential Calculation ◽  
A Site ◽  
Linearized Augmented Plane Wave

We report the estimation of muon sites inside Mn3Sn using density functional theory based on the full-potential linearized augmented plane wave (FLAPW) calculation. Our calculation shows that the Perdew–Burke–Ernzerhof (PBE) Generalized-Gradient Approximation (GGA) functional is closer to the experimental structure compared to the von Barth-Hedin Local Density Approximation (LDA)-optimized geometry. The PBE GGA is therefore subsequently used in FLAPW post-calculation for the electrostatic potential calculation to find the local minima position as a guiding strategy for estimating the muon site. Our result reveals at least two muon sites of which one is placed at the center between two Mn-Sn triangular layers (A site) and the other at the trigonal prismatic site of Sn atom (B site). The total energy of Mn3Sn system in the presence of muon at A site or B site are compared and we find that A site is a more favorable site for muon to stop.

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