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We show that the gap parameter in \textit{semi}-Dirac material induces a large degree of sensitivity for inter-band optical conductivity with respect to the polarization direction. The optical conductivity reveals an abruptly large value at…

Mesoscale and Nanoscale Physics · Physics 2019-02-20 Alestin Mawrie , Bhaskaran Muralidharan

Two-dimensional semi-Dirac models describe a family of novel materials that have anisotropic dispersion with relativistic-type spectrum along one of the spatial directions and non-relativistic along another. In the present paper we perform…

Mesoscale and Nanoscale Physics · Physics 2024-02-21 Daniil Asafov , Ilia Pavlov

Ballistic electrons in phosphorene $pn$ junctions show optical-like phenomena. Phosphorene is modeled by a tight-binding Hamiltonian that describes its electronic structure at low energies, where the electrons behave in the zigzag direction…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 Yonatan Betancur-Ocampo , François Leyvraz , Thomas Stegmann

We design ultra-thin, entirely flat, dielectric lenses using crystal momentum transfer, so-called Umklapp processes, achieving the required wave control for a new mechanism of flat lensing; physically, these lenses take advantage of abrupt…

Optics · Physics 2020-05-06 Gregory J. Chaplain , Richard V. Craster

We present a unified theory of charge carrier transport in 2D Dirac systems with broken mirror inversion and time-reversal symmetries (e.g., as realized in ferromagnetic graphene). We find that the entanglement between spin and pseudospin…

Mesoscale and Nanoscale Physics · Physics 2018-09-21 Manuel Offidani , Aires Ferreira

We show that a graphene pnp junction with a central superconducting electrode acts as a Veselago lens for incoming electrons by focusing them and their phase-conjugated counterpart (holes) into different points of the optical axis. This…

Mesoscale and Nanoscale Physics · Physics 2012-04-11 S. Gomez , P. Burset , W. J. Herrera , A. Levy Yeyati

We investigated the properties of cholesteric liquid crystals (CLCs) being in external static magnetic field directed along the helix axis. We have shown that in the case of the wavelength dependence of magneto-optic activity parameter, and…

Optics · Physics 2023-08-17 A. H. Gevorgyan

We have studied helicity dependent photocurrent (HDP) in Bi-based Dirac semimetal thin films. HDP increases with film thickness before it saturates, changes its sign when the majority carrier type is changed from electrons to holes and…

Mesoscale and Nanoscale Physics · Physics 2020-09-04 Masashi Kawaguchi , Hana Hirose , Zhendong Chi , Yong-Chang Lau , Frank Freimuth , Masamitsu Hayashi

We investigated the transport properties in a normal metal/ferromagnet/normal metal/superconductor junction based on semi-Dirac materials with inverted energy gap. With a scattering matrix approach, we show that the electron transport in…

Superconductivity · Physics 2023-11-03 Yupeng Huang , R. Shen

We demonstrate an inverse designed achromatic, flat, polarization-insensitive diffractive optic element, i.e., multilevel diffractive lens (MDL), operating across a broadband range of UV light (250 nm - 400 nm) via numerical simulations.…

Optics · Physics 2020-06-30 Sourangsu Banerji , Berardi Sensale Rodriguez

Holographic quantum matter exploits the AdS/CFT correspondence to study systems in condensed matter physics. An example of these systems are strongly correlated semimetals, which feature a rich phase diagram structure. In this work, we…

High Energy Physics - Theory · Physics 2024-06-04 Sebastián Bahamondes , Ignacio Salazar Landea , Rodrigo Soto-Garrido

The Dirac equation is a paradigmatic model that describes a range of intriguing properties of relativistic spin-1/2 particles, from the existence of antiparticles to Klein tunneling. However, the Dirac-like equations have found application…

We studied the focusing effect of electron flow induced by a single p-n junction (PNJ) in three-dimensional topological insulator. It is found that the electrons flowing from the n region can be focused at the symmetric position in the p…

Mesoscale and Nanoscale Physics · Physics 2018-05-09 Wang Kai-Tong , Xing Yanxia , Cheung King Tai , Wang Jian , Pan Hui , Zhao Hong-Kang

The advent of Dirac materials has made it possible to realize two dimensional gases of relativistic fermions with unprecedented transport properties in condensed matter. Their photoconductive control with ultrafast light pulses is opening…

The phenomenon of spin-dependent quantum scattering in two-dimensional (2D) pseudospin-1/2 Dirac materials leading to a relativistic quantum chimera was recently uncovered. We investigate spin-dependent Dirac electron optics in 2D…

Mesoscale and Nanoscale Physics · Physics 2024-08-23 Li-Li Ye , Chen-Di Han , Ying-Cheng Lai

In nodal-line semimetals linearly dispersing states form Dirac loops in the reciprocal space, with high degree of electron-hole symmetry and almost-vanishing density of states near the Fermi level. The result is reduced electronic screening…

Novel optical elements containing semitransparent wavelike films embedded into the bulk of transparent material, which form a reflection image without transmitted light distortion, are studied. The dynamic theory of light diffraction by a…

Optics · Physics 2018-05-23 Anatoly M. Smolovich , Valery Chernov

We study the hydrodynamic behavior in two-dimensional, interacting electronic systems with merging Dirac points at charge neutrality. The dispersion along one crystallographic direction is Dirac-like, while it is Newtonian-like in the…

Strongly Correlated Electrons · Physics 2018-05-29 Julia M. Link , Boris N. Narozhny , Egor I. Kiselev , Jörg Schmalian

Veselago pointed out that electromagnetic wave theory allows for materials with a negative index of refraction, in which most known optical phenomena would be reversed. A slab of such a material can focus light by negative refraction, an…

Optics · Physics 2014-02-17 Martin Leder , Christopher Grossert , Martin Weitz

Half a century ago, Veselago proposed left-handed materials with negative permittivity and permeability, in which waves propagate with phase and group velocities in opposite directions. Significant work has been undertaken to attain this…

Mesoscale and Nanoscale Physics · Physics 2016-09-27 Gil-Ho Lee , Geon-Hyoung Park , Hu-Jong Lee