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We study the spin dynamics of a ferromagnetic insulator on which graphene is placed. We show that the Gilbert damping is enhanced by the proximity exchange coupling at the interface. The modulation of the Gilbert damping constant is…

介观与纳米尺度物理 · 物理学 2020-04-16 Yuya Ominato , Mamoru Matsuo

The magnetic field dependence of the electronic properties of \textit{real} single vertical quantum dots in circular and rectangular mesas is investigated within a full three-dimensional multiscale self-consistent approach without any {\it…

The microscopic mechanism of itinerant ferromagnetism is a long-standing problem due to the lack of non-perturbative methods to handle strong magnetic fluctuations of itinerant electrons. We have non-pertubatively studied thermodynamic…

强关联电子 · 物理学 2018-03-01 Shenglong Xu , Yi Li , Congjun Wu

Electronic transport in a graphene-based ferromagnetic/normal/ferromagnetic junction is investigated by means of Landauer-B\"{u}ttiker formulism and the nonequilibrium Green's function technique. For the zigzag edge case, the results show…

介观与纳米尺度物理 · 物理学 2015-05-18 Jiang-chai Chen , Shu-guang Cheng , Shun-Qing Shen , Qing-feng Sun

We analyze the electronic structure of twisted bilayer graphene (TBG) nanoribbons close to the magic angle. We describe a transition from an incomplete to a complete moir\'e structure. By considering zigzag and armchair edge terminations,…

介观与纳米尺度物理 · 物理学 2023-09-14 Elias Andrade , Pierre A. Pantaleón , Francisco Guinea , Gerardo G. Naumis

Electronic and magnetic properties of a system of two charged vacancies in hexagonal shaped graphene quantum dots are investigated using a mean-field Hubbard model as a function of the Coulomb potential strength $\beta$ of the charge…

介观与纳米尺度物理 · 物理学 2020-08-21 E. Bulut Kul , M. Polat , A. D. Güçlü

We have investigated electronic and magnetic properties of graphene nanodisks (nanosize triangular graphene) as well as electromechanical properties of graphene nanojunctions. Nanodisks are nanomagnets made of graphene, which are robust…

介观与纳米尺度物理 · 物理学 2015-03-17 Motohiko Ezawa

The tunable magnetism at graphene edges with lengths of up to 48 unit cells is analyzed by an exact diagonalization technique. For this we use a generalized interacting one-dimensional model which can be tuned continuously from a limit…

强关联电子 · 物理学 2011-05-26 David J. Luitz , Fakher F. Assaad , Manuel J. Schmidt

The magnetic field dependence of energy levels in gapped single- and bilayer graphene quantum dots (QDs) defined by electrostatic gates is studied analytically in terms of the Dirac equation. Due to the absence of sharp edges in these types…

介观与纳米尺度物理 · 物理学 2009-11-13 Patrik Recher , Johan Nilsson , Guido Burkard , Bjoern Trauzettel

We show that for magic-angle twisted bilayer graphene (TBG) away from charge neutrality, although quantum Monte Carlo (QMC) simulations suffer from the sign problem, the computational complexity is at most polynomial at certain integer…

强关联电子 · 物理学 2023-06-22 Xu Zhang , Gaopei Pan , Bin-Bin Chen , Heqiu Li , Kai Sun , Zi Yang Meng

The fascinating quantum many-body states in twisted bilayber graphene (TBG) at magic angle, due to the interplay of Coulomb interactions and the quantum metrics of flat bands, have been well understood both experimentally and theoretically.…

It is shown that apart from well-known factors, like temperature, substrate, and edge reconstruction effects, also the presence of external contacts is destructive for the formation of magnetic moments at the edges of graphene nanoribbons.…

介观与纳米尺度物理 · 物理学 2014-11-18 S. Krompiewski

First principles density-functional theory calculations were performed to investigate quantum confinement and edge effects on the electronic properties of zigzag green phosphorene nanoribbons (ZGPNRs) with edge chemical species including H,…

强关联电子 · 物理学 2020-04-01 Chi Ma , Tianxing Ma , Xihong Peng

Electronic structure and dielectric property in an electronic ferroelectricty, where electric polarization is driven by an electronic charge order without inversion symmetry, are studied. Motivated from layered iron oxides, roles of quantum…

强关联电子 · 物理学 2015-05-19 Tsutomu Watanabe , Sumio Ishihara

A (II,Mn)VI diluted magnetic semiconductor quantum dot with an integer number of electrons controlled with a gate voltage is considered. We show that a single conduction band electron is able to induce a spontaneous collective magnetization…

介观与纳米尺度物理 · 物理学 2009-11-10 J. Fernández-Rossier , L. Brey

In neutral graphene dots the Fermi level coincides with the Dirac points. We have investigated in the presence of a magnetic field several unusual properties of single electron states near the Fermi level of such a rectangular-shaped…

介观与纳米尺度物理 · 物理学 2010-02-24 S. C. Kim , P. S. Park , S. -R. Eric Yang

We perform density functional calculations on one-dimensional zigzag edge graphene nano-ribbons (ZGNRs) of different widths, with and without edge doping including semi-local exchange-correlations. Our study reveals that, although the…

材料科学 · 物理学 2008-06-13 Sudipta Dutta , Swapan K. Pati

Magic angle twisted bilayer graphene (MATBG) presents a fascinating platform for investigating the effects of electron interactions in topological flat bands. The Bistritzer-MacDonald (BM) model provides a simplified quantitative…

强关联电子 · 物理学 2025-03-11 Zhi-Yu Xiao , Shiwei Zhang

We demonstrate theoretically that quantum dots in bilayers of graphene can be realized. A position-dependent doping breaks the equivalence between the upper and lower layer and lifts the degeneracy of the positive and negative momentum…

介观与纳米尺度物理 · 物理学 2007-05-23 J. Milton Pereira , P. Vasilopoulos , F. M. Peeters

This is a review on graphene quantum dots and their use as a host for spin qubits. We discuss the advantages but also the challenges to use graphene quantum dots for spin qubits as compared to the more standard materials like GaAs. We start…

介观与纳米尺度物理 · 物理学 2015-05-18 Patrik Recher , Bjoern Trauzettel