Questions tagged [topological-matter]

Questions about or related to topology in matter modeling.

Filter by
Sorted by
Tagged with
4 votes
0 answers
39 views

Gauge constraint in the definition of the Z2 invariant

Cross-posted at Physics.SE. In Fu and Kane's paper from 2006, the authors define the $\mathbb{Z}_2$ invariant for time-reversal invariant topological insulators as an obstruction to Stoke's theorem, $$...
Sounak Sinha's user avatar
3 votes
1 answer
72 views

How to convert quantum anomalous Hall conductivity values from (Ohm.cm)-1 to e2/hc?

I am currently working on anomalous Hall conductivity calculations using both Wanniertools and wannier90. The output values from these calculations are provided in units of (Ohm$\cdot$cm)-1. I am ...
Alisufyan's user avatar
  • 691
4 votes
1 answer
165 views

What are the precise forms for the SU(2) and rotation matrices in VASP?

Some time ago, I conducted a discussion with Dr. Gui-Bin Liu on topological materials here. One relevant thing he said was: "The format of trace.txt file is only a necessary condition to be used ...
Hongyi Zhao's user avatar
4 votes
0 answers
122 views

How to implement a Weyl semimetal in tight binding? [closed]

I want to study electronic and thermal transport properties of a Weyl semimetal. Until now, I have used only the continuum model hamiltonian ($H=k⋅σ$). As the continuum model has several limitations, ...
SG_commun20's user avatar
11 votes
1 answer
613 views

Does the spin polarised DFT calculation mean broken time reversal symmetry?

Recently, I have got to learn that if time-reversal symmetry and inversion symmetry are present simultaneously in the system we have the following conditions on energy of Bloch's states: $$E_{n,\chi }(...
UJM's user avatar
  • 2,561
9 votes
0 answers
66 views

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

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 ...
TribalChief's user avatar
  • 2,281
6 votes
1 answer
101 views

How to choose half-Brillouin-zone (HBZ) in Fukui & Hatsugai's numerical scheme for the Z2 invariant?

EDIT: Please see my first comment on this question first. In this paper, Fukui and Hatsugai present a numerical scheme for the calculation of the $\mathbb{Z}_2$ index that uses the following ...
TribalChief's user avatar
  • 2,281
12 votes
1 answer
435 views

Band structure of Weyl semimetal?

Weyl semimetals are topological quantum materials whose low energy excitations emerges as massles Weyl Fermions. They have a band touching point near the Fermi level called Weyl node. What is ...
walber97's user avatar
  • 447