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相关论文: Strain-induced quantum phase transitions in magic …

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We investigate twisted bilayer graphene near charge neutrality using a generalized Bistritzer-MacDonald continuum model, accounting for corrugation effects. The Fermi velocity vanishes for particular twist angles properly reproducing the…

强关联电子 · 物理学 2022-09-07 Eric Brillaux , David Carpentier , Andrei A. Fedorenko , Lucile Savary

Strong correlations occur in magic-angle twisted bilayer graphene (MATBG) when the octet of flat moir\'e minibands centered on charge neutrality (CN) is partially occupied. The octet consists of a single valence band and a single conduction…

强关联电子 · 物理学 2024-10-18 Jihang Zhu , Iacopo Torre , Marco Polini , Allan H. MacDonald

Strain tuning is increasingly being recognized as a clean tuning parameter to induce novel behavior in quantum matter. Motivated by the possibility of straining graphene up to $20$ percent, we investigate novel quantum criticality due to…

强关联电子 · 物理学 2017-08-30 S. Arya , M. S. Laad , S. R. Hassan

We consider an alternating Heisenberg spin-$1/2$ antiferromagnetic-ferromagnetic ($AF-F$) chain with the space modulated dominant antiferromagnetic exchange and anisotropic ferromagnetic coupling (tetrameric spin-$1/2$ chain). The…

强关联电子 · 物理学 2017-02-01 J. Vahedi , M. Shabani Arbousara , S. Mahdavifar

Divergent density of states offers the unique opportunity to explore a wide variety of correlated electron physics. In the thinnest limit, this has been predicted and verified in the ultra-flat bands of magic-angle twisted bilayer graphene,…

介观与纳米尺度物理 · 物理学 2022-08-15 Anna M. Seiler , Fabian R. Geisenhof , Felix Winterer , Kenji Watanabe , Takashi Taniguchi , Tianyi Xu , Fan Zhang , R. Thomas Weitz

We introduce and analyze a model that sheds light on the interplay between correlated insulating states, superconductivity, and flavor-symmetry breaking in magic angle twisted bilayer graphene. Using a variational mean-field theory, we…

强关联电子 · 物理学 2021-12-14 Gal Shavit , Erez Berg , Ady Stern , Yuval Oreg

In the 1950's, Pomeranchuk predicted that, counterintuitively, liquid 3He may solidify upon heating, due to a high excess spin entropy in the solid phase. Here, using both local and global electronic entropy and compressibility…

Using calculations on defective graphene from first principles, we herein consider the dependence of the properties of the monovacancy of graphene under isotropic strain, with a particular focus on spin moments. At zero strain, the vacancy…

介观与纳米尺度物理 · 物理学 2010-12-16 E. J. G. Santos , S. Riikonen , D. Sanchez-Portal , A. Ayuela

We analyze the phase diagram of twisted graphene bilayers near a magic angle. We consider the effect of the long range Coulomb interaction, treated within the self consistent Hartree-Fock approximation, and we study arbitrary band fillings.…

强关联电子 · 物理学 2020-07-15 Tommaso Cea , Francisco Guinea

Magic-angle twisted bilayer graphene (MATBG) exhibits a rich variety of electronic states, including correlated insulators, superconductors, and topological phases. Understanding the microscopic mechanisms responsible for these phases…

Proximity effects resulting from depositing a graphene layer on a TMD substrate layer change the dynamics of the electronic states in graphene, inducing spin orbit coupling (SOC) and staggered potential effects. An effective Hamiltonian…

介观与纳米尺度物理 · 物理学 2016-12-21 Abdulrhman M. Alsharari , Mahmoud M. Asmar , Sergio E. Ulloa

We derive a simple formula for the real-space chirality of twisted bilayer graphene that can be related to the cross-product of its sheet currents. This quantity shows well-defined plateaus for the first remote band as function of the gate…

介观与纳米尺度物理 · 物理学 2020-09-02 T. Stauber , J. González , G. Gómez-Santos

Anisotropic hopping in a toy Hofstadter model was recently invoked to explain a rich and surprising Landau spectrum measured in twisted bilayer graphene away from the magic angle. Suspecting that such anisotropy could arise from unintended…

Emergent quantum phases driven by electronic interactions can manifest in materials with narrowly dispersing, i.e. "flat", energy bands. Recently, flat bands have been realized in a variety of graphene-based heterostructures using the…

Twisted bilayer graphene (TBG) hosts a rich landscape of electronic phases arising from the interplay between strong electron-electron interactions and nontrivial band topology. While the flat bands near zero energy are central to many…

介观与纳米尺度物理 · 物理学 2026-02-16 Leonardo A. Navarro-Labastida , Pierre A. Pantaleon , Francisco Guinea , Gerardo G. Naumis

By means of the first-principles calculations combined with the tight-binding approximation, the strain-induced semiconductor-semimetal transition in graphdiyne is discovered. It is shown that the band gap of graphdiyne increases from 0.47…

材料科学 · 物理学 2017-09-13 Hui-Juan Cui , Xian-Lei Sheng , Qing-Bo Yan , Qing-Rong Zheng , Gang Su

Graphene bilayers can condense into a state with spontaneous interlayer phase coherence that supports dissipationless counterflow supercurrents. Here we address the influence of disorder on the graphene bilayer mean-field and…

介观与纳米尺度物理 · 物理学 2009-11-13 R. Bistritzer , A. H. MacDonald

We compute the phase diagram of twisted bilayer graphene near the magic angle where the occurrence of flat bands enhances the effects of electron-electron interactions and thus unleashes strongly-correlated phenomena. Most importantly, we…

强关联电子 · 物理学 2018-12-26 Dante M. Kennes , Johannes Lischner , Christoph Karrasch

Here we study the evolution of local electronic properties of a twisted graphene bilayer induced by a strain and a high curvature. The strain and curvature strongly affect the local band structures of the twisted graphene bilayer; the…

介观与纳米尺度物理 · 物理学 2015-06-05 Wei Yan , Wen-Yu He , Zhao-Dong Chu , Mengxi Liu , Lan Meng , Rui-Fen Dou , Yanfeng Zhang , Zhongfan Liu , Jia-Cai Nie , Lin He

When the perpendicular magnetic flux per unit cell in a crystal is equal to the quantum of magnetic flux, $\Phi_0=h/e$, we enter the 'Hofstadter regime'. The large unit cell of moir\'e materials like magic-angle twisted bilayer graphene…

介观与纳米尺度物理 · 物理学 2024-05-31 Miguel Sánchez Sánchez , Tobias Stauber