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Twisted bilayer graphene (TBG) is known for exhibiting highly correlated phases at magic angles due to the emergence of flat bands that enhance electron-electron interactions. In the TBG chiral model, electronic wave function properties…

Mesoscale and Nanoscale Physics · Physics 2023-09-15 Leonardo A. Navarro-Labastida , Gerardo G. Naumis

We calculate that the electron states of strained self-assembled Ge/Si quantum dots provide a convenient two-state system for electrical control. An electronic state localized at the apex of the quantum dot is nearly degenerate with a state…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 C. E. Pryor , M. E. Flatté , J. Levy

Rotated graphene multilayers form a new class of graphene related systems with electronic properties that drastically depend on the rotation angles. It has been shown that bilayers behave like two isolated graphene planes for large rotation…

Mesoscale and Nanoscale Physics · Physics 2012-09-11 G. Trambly de Laissardière , D. Mayou , L. Magaud

We present an analytically solvable model of $P$ colinear, two-dimensional quantum dots, each containing two electrons. Inter-dot coupling via the electron-electron interaction gives rise to sets of entangled ground states. These ground…

Condensed Matter · Physics 2009-10-28 Simon C. Benjamin , Neil F. Johnson

We show that characteristics of the electron's form factor in two-dimensional materials are observable in quasiparticle interference (QPI) spectrum. We study QPI in twisted bilayer graphene using real-space tight-binding calculations…

Mesoscale and Nanoscale Physics · Physics 2025-09-16 D. -H. -Minh Nguyen , Francisco Guinea , Dario Bercioux

Experimental realization of graphene-based stadium-shaped quantum dots (QDs) have been few and incompatible with scanned probe microscopy. Yet, direct visualization of electronic states within these QDs is crucial for determining the…

Bilayer graphene (BLG)-based quantum devices represent a promising platform for emerging technologies, such as quantum computing and spintronics. However, their intrinsically weak spin-orbit coupling (SOC) complicates spin and valley…

We show that spin-orbit coupling in a quantum dot molecule allows for coherent manipulation of two electron spin states using Raman transitions. Such two-electron spin states defined by the singlet and triplet states of two exchange coupled…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Hakan E. Türeci , J. M. Taylor , A. Imamoglu

We describe the gated bilayer graphene system when it is subjected to intense terahertz frequency electromagnetic radiation. We examine the electron band structure and density of states via exact diagonalization methods within Floquet…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 D. S. L. Abergel , Tapash Chakraborty

A system similar to gapped graphene (for example, fluorinated) containing two or more electron valleys is considered. It is assumed that the material has a sector cut and is deformed in the plane and the the cut edges are connected to form…

Mesoscale and Nanoscale Physics · Physics 2021-01-14 M. V. Entin , L. I. Magarill

The electronic properties of semiconductor, vertical, double quantum dot systems with few electrons are investigated by means of analytic, configuration-interaction, and mean-field methods. The combined effect of a high magnetic field,…

Condensed Matter · Physics 2009-10-22 Juan Jose Palacios , Pawel Hawrylak

The electronic properties of bilayer graphene with a magnetic quantum dot and a magnetic quantum ring are investigated. The eigenenergies and wavefunctions of quasiparticle states are calculated analytically by solving decoupled…

Mesoscale and Nanoscale Physics · Physics 2021-11-17 Daehan Park , Heesang Kim , Nammee Kim

Berry phase plays an important role in determining many physical properties of quantum systems. However, a Berry phase altering energy spectrum of a quantum system is comparatively rare. Here, we report an unusual tunable valley polarized…

Mesoscale and Nanoscale Physics · Physics 2021-08-18 Ya-Ning Ren , Qiang Cheng , Qing-Feng Sun , Lin He

We report on the observation of periodic conductance oscillations near quantum Hall plateaus in suspended graphene nanoribbons. They are attributed to single quantum dots that form in the narrowest part of the ribbon, in the valleys and…

Mesoscale and Nanoscale Physics · Physics 2016-06-28 E. Tóvári , P. Makk , P. Rickhaus , C. Schönenberger , S. Csonka

Bilayer graphene -- two coupled single graphene layers stacked as in graphite -- provides the only known semiconductor with a gap that can be tuned externally through electric field effect. Here we use a tight binding approach to study how…

Mesoscale and Nanoscale Physics · Physics 2010-04-29 Eduardo V. Castro , N. M. R. Peres , J. M. B. Lopes dos Santos , F. Guinea , A. H. Castro Neto

Bilayer graphene (BLG) at the charge neutrality point (CNP) is strongly susceptible to electronic interactions, and expected to undergo a phase transition into a state with spontaneous broken symmetries. By systematically investigating a…

Mesoscale and Nanoscale Physics · Physics 2012-08-01 Wenzhong Bao , Jairo Velasco , Fan Zhang , Lei Jing , Brian Standley , Dmitry Smirnov , Marc Bockrath , Allan MacDonald , Chun Ning Lau

Electrons most often organize into Fermi-liquid states in which electron-electron interactions play an inessential role. A well known exception is the case of one-dimensional (1D) electron systems (1DES). In 1D the electron Fermi-surface…

Strongly Correlated Electrons · Physics 2010-01-09 Fan Zhang , Hongki Min , Marco Polini , A. H. MacDonald

We report on integer and fractional quantum Hall states in a stack of two twisted Bernal bilayer graphene sheets. By exploiting the momentum mismatch in reciprocal space, we suppress single particle tunneling between both bilayers. Since…

Mesoscale and Nanoscale Physics · Physics 2023-06-08 Soyun Kim , Dohun Kim , Kenji Watanabe , Takashi Taniguchi , Jurgen. H. Smet , Youngwook Kim

Due to Klein tunneling, electrostatic confinement of electrons in graphene is not possible. This hinders the use of graphene for quantum dot applications. Only through quasi-bound states with finite lifetime has one achieved to confine…

Mesoscale and Nanoscale Physics · Physics 2018-05-29 Hasan M. Abdullah , M. Van der Donck , H. Bahlouli , F. M. Peeters , B. Van Duppen

We report the preparation and readout of multielectron high-spin states, a three-electron quartet, and a four-electron quintet, in a gate-defined GaAs/AlGaAs single quantum dot using spin filtering by quantum Hall edge states coupled to the…

Mesoscale and Nanoscale Physics · Physics 2021-09-01 H. Kiyama , K. Yoshimi , T. Kato , T. Nakajima , A. Oiwa , S. Tarucha