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A semiconductor quantum dot (QD) can generate highly indistinguishable single-photons at a high rate. For application in quantum communication and integration in hybrid systems, control of the QD optical properties is essential.…

Exploring the quantum geometric properties of solids beyond their topological aspects has become a key focus in current solid-state physics research. We derive the geometric formula for optical conductivity from the quantum metric tensor,…

Strongly Correlated Electrons · Physics 2025-03-25 Chang-geun Oh , Sun-Woo Kim , Kun Woo Kim , Bartomeu Monserrat , Jun-Won Rhim

Graphene quantum dots (GQDs) not only have potential applications on spin qubit,but also serve as essential platforms to study the fundamental properties of Dirac fermions, such as Klein tunneling and Berry phase. By now, the study of…

Mesoscale and Nanoscale Physics · Physics 2021-11-24 Si-Yu Li , Lin He

We propose and demonstrate a novel range of models to accurately determine the optical properties of nitrogen-free carbon quantum dots (CQDs) with ordered graphene layered structures. We confirm the results of our models against the full…

Mesoscale and Nanoscale Physics · Physics 2023-02-15 D. W. Boukhvalov , V. Yu. Osipov , B. T. Hogan , A. Baldycheva

Optical properties of graphene are explored by using the generalized tight-binding model. The main features of spectral structures, the form, frequency, number and intensity, are greatly enriched by the complex relationship among the…

Computational Physics · Physics 2016-07-20 Chiun-Yan Lin , Thi-Nga Do , Yao-Kung Huang , Ming-Fa Lin

We show that for graphene with any finite difference in the on-site energy between the two sub-lattices ($\Delta$), The optical absorption edge is determined by the $\Delta$. The universal conductance will be broken and the conductance near…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Lei Chen , Zhongshui Ma , C. Zhang

The conductance through a quantum point contact created by a sharp and hard metal tip on the graphite surface has features which to our knowledge have not been encountered so far in metal contacts or in nanowires. In this paper we first…

Materials Science · Physics 2009-10-31 C. Kilic , H. Mehrez , S. Ciraci

In this article, we investigate the temperature and chemical potential dependence of the optical conductivity of graphene, within a field theoretical representation in the continuum approximation, arising from an underlying tight-binding…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 Horacio Falomir , Enrique Muñoz , Marcelo Loewe , Renato Zamora

We study theoretically the single-electron triangular zigzag graphene quantum dot in uniform in-plane electric fields. The far-infrared absorption spectra of the dot are calculated by the tight-binding method. The energy spectra and the…

Mesoscale and Nanoscale Physics · Physics 2018-03-14 Qing-Rui Dong , Yan Li , Chun-Xiang Liu

In this paper, we used the 8-band k$\cdot$p model with valence force field considerations to investigate the effect of size and shape on electronic and optical properties of cadmium selenide quantum dots. Major factors related to their…

Materials Science · Physics 2017-11-08 Yincheng Liu , Sumanta Bose , Weijun Fan

We study the conductance spectrum of graphene quantum dots, both single and multiple cases. The single electron tunneling phenomenon is investigated and the periodicity, amplitude and line shape of the Coulomb blockade oscillations at low…

Mesoscale and Nanoscale Physics · Physics 2009-11-17 Qiong Ma , Tao Tu , Zhi-Rong Lin , Guang-Can Guo , Guo-Ping Guo

The layer stacking morphology in nanocarbons is paramount for achieving new properties and outperforming applications. Here, we demonstrate that graphene quantum dots (GQDs) retain crystallinity and a stacking structure from CVD graphene…

The structure stability and electronic properties of edge carboxylated hexagonal and triangular graphene quantum dots are investigated by using density functional theory. The calculated binding energies show that the hexagonal clusters with…

Mesoscale and Nanoscale Physics · Physics 2018-03-14 Hazem Abdelsalam , Hanan Elhaes , Medhat A. Ibrahim

We show that the optical transparency of suspended graphene is defined by the fine structure constant, alpha, the parameter that describes coupling between light and relativistic electrons and is traditionally associated with quantum…

Mesoscale and Nanoscale Physics · Physics 2008-06-08 R. R. Nair , P. Blake , A. N. Grigorenko , K. S. Novoselov , T. J. Booth , T. Stauber , N. M. R. Peres , A. K. Geim

We study electron scattering in graphene quantum dots (GQDs) under the combined influence of a magnetic field, an energy gap, and circularly polarized laser irradiation. Using the Floquet approach and the Dirac equation, we derive the…

Mesoscale and Nanoscale Physics · Physics 2025-01-30 Ahmed Bouhlal , Mohammed El Azar , Aotmane En Naciri , Elmustapha Feddi , Ahmed Jellal

We compute the optical conductivity for an out-of-plane deformation in graphene using an approach based on solutions of the Dirac equation in curved space. Different examples of periodic deformations along one direction translates into an…

Mesoscale and Nanoscale Physics · Physics 2014-05-05 A. J. Chaves , T. Frederico , O. Oliveira , W. de Paula , M. C. Santos

Graphene nanoribbons display an imperfectly understood transport gap. We measure transport through nanoribbon devices of several lengths. In nanoribbons of length greater than or equal to 250 nm we observe transport through multiple quantum…

Mesoscale and Nanoscale Physics · Physics 2009-01-02 Kathryn Todd , Hung-Tao Chou , Sami Amasha , David Goldhaber-Gordon

The computation of the optical conductivity of strained and deformed graphene is discussed within the framework of quantum field theory in curved spaces. The analytical solutions of the Dirac equation in an arbitrary static background…

Materials Science · Physics 2015-12-01 W. de Paula , a. Chaves , O. Oliveira , T. Frederico

We study electronic and optical properties of single layer phosphorene quantum dots with various shapes, sizes, and edge types (including disordered edges) subjected to an external electric field normal to the structure plane. Compared to…

Mesoscale and Nanoscale Physics · Physics 2017-08-29 V. A. Saroka , I. Lukyanchuk , M. E. Portnoi , H. Abdelsalam

The optical conductivity of graphene, bilayer graphene, and graphite in quantizing magnetic fields is studied. Both dynamical conductivities, longitudinal and Hall's, are analytically evaluated. The conductivity peaks are explained in terms…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 L. A. Falkovsky