arXiv subjects

Badie Ghavami

Publications and source records attributed to Badie Ghavami.

6 recordsLinked to original sources

arXiv2025

High-temperature superconducting Majorana fermions platforms in the layered Kitaev Materials: Case study of $Li_2IrO_3$

Recent advances in Kitaev materials have highlighted their potential to host Majorana fermions without or high-temperature of superconductivity. In this research, we propose $Li_2IrO_3$ as a promising High-temperature superconducting platform supporting Majorana edge modes due to its strong spin-orbit coupling, honeycomb lattice structure, and proximity to a quantum spin liquid (QSL) phase. A theoretical and numerical framework based on the Kitaev-Heisenberg Hamiltonian is developed to model spin interactions in $Li_2IrO_3$. Here, the existence of topological zero-energy states is demonstrated, and their signatures in the edge-localized spectral weight are identified. A device concept based on this material is also proposed with potential industrial applications in spintronics, magnetic field sensing, and topological quantum memory.

cond-mat.mes-hall↗

arXiv2025

Ground State Energy of He molecule Using a Four-Qubit Photonic Processor with the Variational Quantum Eigensolver

To understand the properties and interactions of materials, and determining the ground state energies is one of the important challenges in quantum chemistry, materials science, and quantum mechanics, where quantum computing can play an important role for studying the properties of materials. In this study, we have explored the quantum processor application to compute the He molecule ground state energy which utilizes the Variational Quantum Eigensolver (VQE) algorithm. In here, we have implemented VQE on a state-of-the-art quantum processor, optimizing a parameterized quantum circuit to minimize the energy expectation value of the He molecule's Hamiltonian on the four qubits processor. The obtained results of this work show a significant improvement in accuracy compared to classical computational methods, such as Hartree-Fock and density functional theory, which demonstrate the compute potential of quantum algorithms in quantum many-body problems. Thus, these results demonstrate the advantages of quantum computing in achieving high accuracy in simulations of molecular and material properties, and pave the way for future applications in more complex systems. This work highlights the potential of quantum processors in the fields of quantum chemistry, computational physics, and data science.

quant-ph↗

arXiv2023

Optical absorption tensors based on C$_{70}$ trimers and polymers

The optical absorption spectrum of $C_{60}$-dimers and polymers was investigated by Kikuo et al. in 1996\cite{harigaya1996charge}. As a compliment to these earlier studies, the optical absorption spectrum of the $C_{70}$ fullerene has been investigated in the present study. The main purpose was then to compare the absorption spectrum of the $C_{70}$-dimers and trimers and, more specifically, to clarify the effect of these molecular structures on the absorption spectrum. What is most important and decisive is then the value of the conjugation parameter of these $C_{70}$-based molecules. In the present study, a tight-binding model was used in calculating the optical absorption spectra of both $C_{70}$ dimers and polymers, as well as $C_{70}$ trimers and polymers. The change in conjugation parameter for each of these species was found to cause variations in the corresponding optical absorption spectrum. It was found that the absorption tensor of the $C_{70}$ trimer and the polymer was, depending on the value of the conjugation parameters $b=0.5$ and $b=0.8$. The situation was almost the same for the conjugation parameters $b=0.1$ and $b=0.2$. In addition, the value of the band gap was also different depending on the different conjugation parameters, with a reduced value for the larger values of this parameter. As a conclusion, smaller values of the conjugation parameter were not found to have a large effect on the absorption spectrum of the $C_{70}$-dimers and trimers, or in other words, the effect was hardly visible. On the contrary, the larger values caused a drastic change in the optical absorption spectrum of the $C_{70}$-dimers and trimers.

cond-mat.mes-hall↗

arXiv2018

Theoretical investigation of charge transport in germanium doped phosphorene nanoribons using DFT + NEGF

New two diemensional structures nanoribbon including phosphorus and germanium atoms are introduced for the nanoelectronic applications. Under various bias voltages, the electronic transport in the systems have been studied within the noneqilibrium Green's function formalism. The $I-V$ characteristics have been extracted. DOS and $T(E,V_{bias})$ have been investigated and show that the charge transport occurs when the bias voltage reaches about 1 \textit{V}. The calculated MPSH shows that the spatial distribution of orbital levels has been affected by the electrodes. The studied structures have a bandgap of about 0.7 \textit{eV} which absorbs light in the visible range and thus could be an interesting contender for solar cells applications.

cond-mat.mes-hall↗

arXiv2015

Varistor characteristics of a nano-device containing graphene and oxidized graphene: Verification by DFT + NEGF

Electron transport and quantum conductance through an armchair graphene and its oxidized graphene- containing form were investigated by the density functional theory (DFT) method and the implementation of the non-equilibrium Green function (NEGF) approach. The computed $I-V_b$(current as a function of bias voltage) characteristic of the studied systems showed the tunneling phenomenon in bias and gate voltages considered. Along with the transport properties, electronic properties including density of states (DOS) were calculated in the studied systems. A close examination of the results showed that the $I-V_b$ curve for graphene behaved $I\propto V_be^{λV_b}$ like at some bias voltages, while for the oxidized graphene-containing form, its trend was the same as that of a Voltage Dependent Resistor (VDR-VARiable resISTOR), $I\propto V_b^β$, at the whole range of the applied bias.

cond-mat.mes-hall↗

arXiv2014

The Quantum Transport of Pyrene and its Silicon-Dopped Variant: A DFT-NEGF Approach

The quantum conductance properties of pyrene molecule and its silicone-doped variant between semi-infinite aluminum nano-chains have been investigated by using the density functional theory (DFT) combined with the non-equilibrium Green function (NEGF) method. Electronic transport computations have been carried out in the bias voltage range valued from 0.0 to +2.0 V divided by 0.1 V step-sized intervals and under the gate potentials including -3.0, 0.0 and +3.0 V. The Current-bias curves at the considered bias and gates potential show regions with negative differential resistance (NDR). The effects of the variations of the gates on the NDR characteristics including the number of NDR peaks, bias range and current maxima's at the peak have been discussed and the potential applicability of the devices as nano-switches and multi-nanoswitches have been discussed. The transmission spectrum along with the density of states (DOS) and projected DOS (PDOS) have also been presented and transmission variations has been discussed in terms of the DOS and PDOS variations.Quantum conductance at zero bias versus gate potential has been also presented and discussed.

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