Models

Here we define some models, that can be used to test the code, or just to play around

wannierberri.models.Chiral(delta=2, hop1=1, hop2=0.3333333333333333, phi=0.3141592653589793, hopz_right=0.0, hopz_left=0.2, hopz_vert=0.0)

Create a chiral model - a chirally stacked haldane model -

using PythTB Following the article by Yoda,Yokoyama & Murakami 2018 this model breaks time-reversal and inversion, so it can be used to test almost any quantity. Has a symmetry C3z

Parameters:

• delta (float) – difference between the on-site potentials of the two atoms

• hop1 (float) – nearest-neighbour in-plane hopping

• hop2 (float) – magnitude of next nearest-neighbour in-plane hopping

• phi (float) – phase of next nearest-neighbour in-plane hopping

• hopz_vert (float or complex) – interlayer vertical hopping

• hopz_right (float or complex) – chiral right-handed hopping in the z direction

• hopz_left (float or complex) – chiral left-handed hopping in the z direction

• Note –

• -------- –

• pythtb) (PythTB should be installed to use this (pip install) –

wannierberri.models.Haldane_ptb(delta=0.2, hop1=-1.0, hop2=0.15, phi=1.5707963267948966)

same as Haldane_tbm(), but uses PythTB

Note:

PythTB should be installed to use this (pip install pythtb)

wannierberri.models.Haldane_tbm(delta=0.2, hop1=-1.0, hop2=0.15, phi=1.5707963267948966)

Defines a Haldane model within TBmodels

Parameters:

• delta (float) – difference between the on-site potentials of the two atoms

• t (float) – nearest-neighbour hopping

• hop2 (float) – magnitude of next nearest-neighbour hopping

• phi (float) – phase of next nearest-neighbour hopping

• Note –

• -------- –

• tbmodels) (TBmodels should be installed to use this (pip install) –