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Lecture 2 : Berry Phase and Chern number — Physics …

2019-10-15 · Berry Phase review¶ Assuming a physical system is depended on some parameters \(\mathbf{R}=(R_1,R_2,\cdots,R_N)\), we have the snapshot Hamiltonian \(H(\mathbf{R})\), its eigen-values and eigen-states:

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Local Berry curvature signatures in dichroic angle ...

For graphene-like insulating systems, the Berry curvature and the orbital polarization for the three possible scenarios are shown in Fig. 1. Graphene (neglecting the SOC) has inversion symmetry, and respective sublattice sites on the honeycomb lattice are equivalent; hence ? z ( k ) is zero in both spin channels, giving rise to a Dirac ...

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Berry curvature in graphene: a new approach | …

In the present paper we have directly computed the Berry curvature terms relevant for graphene in the presence of an inhomogeneous lattice distortion. We have employed the generalized Foldy–Wouthuysen framework, developed by some of us. We show that a non-constant lattice distortion leads to a valley–orbit coupling which is responsible for a valley–Hall effect.

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Berry Curvature in Graphene: A New Approach – arXiv …

Abstract: In the present paper we have directly computed the Berry curvature terms relevant for Graphene in the presence of an inhomogeneous lattice distortion. We have employed the generalized Foldy Wouthuysen framework, developed by some of us [4, 5, 6].We show that a non-constant lattice distortion leads to a valley-orbit coupling which is responsible to a valley-Hall effect.

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Berry curvature in graphene: a new approach - …

In the present paper we have directly computed the Berry curvature terms relevant for graphene in the presence of an inhomogeneous lattice distortion. We have employed the generalized Foldy-Wouthuysen framework, developed by some of us. We show that a non-constant lattice distortion leads to a valley-orbit coupling which is responsible for a valley-Hall effect.

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Berry Curvature and Nonlocal Transport …

Since the Berry curvature is expected to induce a transverse conductance, we have experimentally verified this feature through nonlocal transport measurements, by fabricating three antidot graphene samples with a triangular array of holes, a fixed periodicity …

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Visualization and Manipulation of Bilayer Graphene …

2020-12-9 · Electrostatically defined quantum dots (QDs) in Bernal stacked bilayer graphene (BLG) are a promising quantum information platform because of their long spin decoherence times, high sample quality, and tunability. Importantly, the shape of QD states determines the electron energy spectrum, the interactions between electrons, and the coupling of electrons to their environment, all of which are ...

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Unraveling materials Berry curvature and Chern …

The Berry curvature of this artificially inversion-broken graphene band is calculated and presented in Fig. 2A, Lower . Onto the self-consistently converged ground state, we applied a constant and uniform static E field along the x direction (E = E 0 x ^ = 1.45 × 1 0 − 3 x ^ V/Å) and performed the time propagation.

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Phys. Rev. X 7, 031043 (2017) - Berry Curvature and ...

Antidot graphene, a sheet of carbon atoms with carefully arranged patterns of holes, has electronic properties that differ from pristine graphene. One way to quantify this difference is with a mathematical quantity called Berry curvature. A new analysis shows that antidot graphene has nonzero curvature, which leads to interesting electron behavior.

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Detecting the Berry curvature in photonic graphene ...

Detecting the Berry curvature in photonic graphene. R. L. Heinisch. Institut für Physik, Ernst‐Moritz‐Arndt‐Universität Greifswald, 17487 Greifswald, Germany. Search for more papers by this author. H. Fehske. Corresponding Author. E-mail address: fehske@physik.uni-greifswald.de.

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Ultrafast optical currents in gapped graphene - …

2019-11-4 · Such broadening of the Berry curvature, which can be tuned by the band gap, results in nontrivial topological properties of gapped graphene [19, 25, 27, 28]. One of such properties is a recently predicted topological resonance, which produces finite valley polarization in TMDCs and gapped graphene [ 18 , 29 ].

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Derivation of the Berry Curvature and Bloch Magentic ...

Also, the Berry curvature equation listed above is for the conduction band. I should also mention at this point that Xiao has a habit of switching between k and q, with q being the crystal momentum measured relative to the valley in graphene. With this information in hand I will attempt to derive these equations with the help of Mathematica.

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Derivation of the Berry Curvature and Bloch Magentic ...

Also, the Berry curvature equation listed above is for the conduction band. I should also mention at this point that Xiao has a habit of switching between k and q, with q being the crystal momentum measured relative to the valley in graphene. With this information in hand I will attempt to derive these equations with the help of Mathematica.

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Is the Berry curvature in perfect monolayer graphene …

2020-9-19 · Is the Berry curvature in perfect monolayer graphene zero? Ask Question Asked 3 years, 9 months ago. Active 3 years, 9 months ago. Viewed 2k times 3. 10 $\begingroup$ I'm struggling to reconcile two concepts and understand if the Berry curvature in graphene …

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Weyl Semi-metal — Physics 0.1 documentation

2019-10-15 · The Chern number of this two-dimensional band structure is given by the Berry curvature integration: \(\frac{1}{2\pi}\int\mathscr{F}dk_zd\lambda\), which, by the Stokes theorem, simply corresponds to the net monopole density enclosed within the torus. This is obtained by summing the chiralities of the enclosed Weyl nodes.