Questions tagged [berry-phase]

Questions relating to properties that depend on Berry phase-like quantities

11 questions with no upvoted or accepted answers
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Orbital magnetization in periodic solids

The orbital magnetization in periodic solids has been nicely described by the so-called modern theory of magnetization [1,2,3,4]. $$\tag{1} \mathcal{M}_{orb} = -\frac{1}{2} \Im \sum_{n,\mathbf{k}} f_{...
9
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0answers
54 views

What is special about valley-focused Hamiltonians that make them give quantized/rational (valley) Chern numbers?

I have been thinking about so-called valley Chern numbers $C_v$ and associated topological phenomena. To my knowledge, they are usually applicable when inter-valley scattering is suppressed, leaving ...
8
votes
0answers
84 views

What are some types of topologically-relevant band degeneracies in contemporary 2D condensed matter research?

Cross-posted on Physics.SE. In the study of 2D condensed matter systems, I have seen several kinds of band degeneracies. I call 'bands' the eigenvalues to the time-independent Schrodinger equation, ...
8
votes
0answers
94 views

Example of a standard/archetypal/simple 4-band gapped condensed matter model with analytic results?

I am looking to study Berry phase-like phenomena in a gapped 4-band material model. In particular, I want to numerically and analytically calculate the Abelian Berry curvature integral of each band ...
7
votes
0answers
35 views

Can the anomalous Hall effect only be applied to magnetic materials?

As I understand the anomalous Hall effect, in materials with a strong spin-orbit coupling, the intrinsic deflection effect is dominant over the side jump and skew scattering effects. In the intrinsic ...
7
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0answers
130 views

How to fix gauge in Quantum ESPRESSO?

I am trying to use Quantum ESPRESSO to manually calculate the Berry phase using the Berry connection, due to evolution along a closed loop in k-space. I want to do this manually instead of using ...
6
votes
0answers
54 views

Berry Curvature with VASP+WANNIER90

I searched in the tutorials in WANNIER90 and example 18 says that the calculation of the Berry curvature requires the "recent version of the pw2wannier90 ...
6
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0answers
26 views

How to plot Berry curvature flux by considering plane in momentum space?

I want to plot the berry curvature flux by considering $k_x$ and $k_y$ plane in momentum space. I have experience running DFT calculations in Quantum ESPRESSO. I have tried reading the user manual of ...
6
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0answers
34 views

Example of 2D k-space models allowing interband transitions after a closed-loop trajectory?

I have been mainly exposed to 2D momentum-space condensed matter models in the context of Berry-related topology. I now want to study models where, if I take a closed loop in momentum space, I will ...
5
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0answers
56 views

Z2 topological index: Is this unconventional formula summed over just filled bands, or all bands?

The $\mathbb{Z}_2$ topological index is usually defined in terms of the Pfaffian of the overlap matrix, as defined by eq. 4 of Kane and Mele's paper: $$ P(k)=\text{Pf}[\langle u_i(k) | \Theta | u_j(k) ...
5
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0answers
134 views

Why does numerical computation of Berry curvature give me a correct Berry phase when it is supposed to diverge?

I implemented the standard numerical algorithm for calculating the Berry curvature in MATLAB. For a given 2D system, I can visualize the Berry curvature over parameter space. If I sum the Berry ...