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We show analytically that the ability of Dirac materials to localize an electron in both a barrier and a well can be utilized to open a pseudo-gap in graphene's spectrum. By using narrow top-gates as guiding potentials, we demonstrate that…

Mesoscale and Nanoscale Physics · Physics 2020-11-17 R. R. Hartmann , M. E. Portnoi

We show that if the solutions to the (2+1)-dimensional massless Dirac equation for a given 1D potential are known, then they can be used to obtain the eigenvalues and eigenfunctions for the same potential, orientated at an arbitrary angle,…

Mesoscale and Nanoscale Physics · Physics 2023-07-07 R. A. Ng , A. Wild , M. E. Portnoi , R. R. Hartmann

The double-well problem for the two-dimensional Dirac equation is solved for a family of quasi-one-dimensional potentials in terms of confluent Heun functions. We demonstrate that for a double well separated by a barrier, both the energy…

Mesoscale and Nanoscale Physics · Physics 2021-01-01 R. R. Hartmann , M. E. Portnoi

Hyperbolic materials are receiving significant attention due to their ability to support electromagnetic fields with arbitrarily high momenta and, hence, to achieve very strong light confinement. Here, based on first-principles calculations…

Materials Science · Physics 2021-08-25 Zahra Torbatian , Dino Novko , Reza Asgari

The study of waveguide propagating modes is essential for achieving directional electronic transport in two-dimensional materials. Simultaneously, exploring potential gaps in these systems is crucial for developing devices akin to those…

Mesoscale and Nanoscale Physics · Physics 2023-07-03 V. G. Ibarra-Sierra , E. J. Robles-Raygoza , J. C. Sandoval-Santana , R. Carrillo-Bastos

We introduce two-dimensional borane, a single-layered material of BH stoichiometry, with promising electronic properties. We show that, according to Density Functional Theory calculations, two-dimensional borane is semimetallic, with two…

Materials Science · Physics 2017-12-01 Miguel Martinez-Canales , Timur R. Galeev , Alexander I. Boldyrev , Chris J. Pickard

We show that a planar array of bipolar waveguides in graphene can be used to engineer gapped and tilted two-dimensional Dirac cones within the electronic band structure. The presence of these gapped and tilted Dirac cones is demonstrated…

Mesoscale and Nanoscale Physics · Physics 2024-12-02 A. Wild , R. R. Hartmann , E. Mariani , M. E. Portnoi

We obtain exact solutions to the two-dimensional (2D) Dirac equation for the one-dimensional P\"oschl-Teller potential which contains an asymmetry term. The eigenfunctions are expressed in terms of Heun confluent functions, while the…

Mesoscale and Nanoscale Physics · Physics 2017-10-10 R. R. Hartmann , M. E. Portnoi

In this paper, we study the massive Dirac equation with the presence of the Morse potential in polar coordinate. The Dirac Hamiltonian is written as two second-order differential equations in terms of two spinor wavefunctions. Since the…

Quantum Physics · Physics 2021-04-27 Z. Zali , Alireza Amani , J. Sadeghi , B. Pourhassan

We decipher the microscopic mechanism of the formation of tilt in the two-dimensional Dirac cone of $8Pmmn$ borphene. In our ab-initio calculations, we identify relevant low-energy degrees of freedom on the $8Pmmn$ lattice and find that…

Materials Science · Physics 2023-08-07 Yasin Yekta , Hanif Hadipour , S. A. Jafari

We predict nonlinear optical polarization rotation in two dimensional massless Dirac systems including graphene and 8-$Pmmn$ borophene. When illuminated, a continuous wave optical field leads to a nonlinear steady state of photo-excited…

Mesoscale and Nanoscale Physics · Physics 2018-05-23 Ashutosh Singh , Saikat Ghosh , Amit Agarwal

The interband optical absorption of linearly polarised light by two-dimensional (2D) semimetals hosting tilted and anisotropic Dirac cones in the bandstructure is analysed theoretically. Super-critically tilted (type-II) Dirac cones are…

Mesoscale and Nanoscale Physics · Physics 2022-06-09 A. Wild , E. Mariani , M. E. Portnoi

We construct the most generic Hamiltonian of the $8Pmmn$ structure of borophene sheet in presence of spin-orbit, as well as background electric and magnetic fields. In addition to spin and valley Hall effects, this structure offers a…

Mesoscale and Nanoscale Physics · Physics 2019-06-28 Tohid Farajollahpour , Zahra Faraei , S. A. Jafari

First-principles calculations on monolayer 8-{\it Pmmn} borophene are reported to reveal unprecedented electronic properties in a two-dimensional material. Based on a Born effective charge analysis, 8-{\it Pmmn} borophene is the first…

Materials Science · Physics 2016-08-18 Alejandro Lopez-Bezanilla , Peter B. Littlewood

Polymorph of 8-Pmmn borophene exhibits anisotropic tilted Dirac cones. In this work, we explore the consequences of the tilted Dirac cones in magnetotransport properties of a periodically modulated borophene. We evaluate modulation induced…

Mesoscale and Nanoscale Physics · Physics 2017-12-13 SK Firoz Islam , A. M. Jayannavar

Two-dimensional semimetals with tilted Dirac cones in the electronic band structure are shown to exhibit spatial separation of carriers belonging to different valleys under illumination. In stark contrast to gapped Dirac materials this…

Mesoscale and Nanoscale Physics · Physics 2023-11-08 A. Wild , E. Mariani , M. E. Portnoi

Searching for new states of matter and unusual quasiparticles in emerging materials and especially low-dimensional systems is one of the major trends in contemporary condensed matter physics. Dirac materials, which host quasiparticles which…

Mesoscale and Nanoscale Physics · Physics 2017-10-13 C. A. Downing , M. E. Portnoi

The energy spectrum for the problem of 8-Pmmn borophene's electronic carriers under perpendicular incidence of electromagnetic waves is studied without the use of any perturbative technique. This allows to study the effects of very strong…

Mesoscale and Nanoscale Physics · Physics 2019-01-16 Abdiel E. Champo , Gerardo G. Naumis

The list of two dimensional Dirac systems with a tilt in their Dirac cone spectrum is expanding, and now in addition to organic system $\alpha$(BEDT-TTF)$_2$I$_3$ includes the two dimensional $8Pmmn$-borophene sheet, which allows for…

Strongly Correlated Electrons · Physics 2018-11-13 Z. Jalali-Mola , S. A. Jafari

We propose a design of two-dimensional bi-anisotropic meta-waveguide exhibiting topologically nontrivial photonic phase and robust photonic transport. The structure proposed represents a waveguide formed by a periodic array of metallic…

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