All Questions
Tagged with topological-insulators quantum-hall-effect
22
questions with no upvoted or accepted answers
10
votes
1
answer
268
views
Is there any heat loss in chiral edge channels of topological insulators?
If we are working with nontrivial topological insulator with broken time reversal symmetry then we can expect that we have some chiral edge states. Chiral states have the property that the current can ...
- 1,795
4
votes
0
answers
110
views
Does Hall conductivity change sign with chemical potential?
The transverse conductivity $\sigma_{xy}$ at zero frequency is quantized when the chemical potential $\mu$ is within the gap for a topological system. A typical plot of $\sigma_{xy}(\mu)$ is like the ...
- 3,701
4
votes
0
answers
878
views
Laughlin's topological argument
I have a confusion about understanding the Laughlin's topological argument on Hall conductivity quantization.
This argument states that the Hall conductivity is
$$
\sigma_{xy}=\frac{e}{h}Q,
$$
where $...
- 2,333
4
votes
0
answers
1k
views
TKNN invariant changes due to continuous deformation of parameter space
Naively, I would assume that a topological invariant remains invariant under continuous deformations of whatever space the invariant belongs to. In the case of topological insulators, this space is ...
- 949
3
votes
0
answers
78
views
Zero frequency limit of Hall conductivity not quantized?
The transverse conductivity $\sigma_{xy}$ at zero frequency is quantized when the chemical potential $\mu$ is within the gap for a topological system, such as quantum Hall effect and Haldane model. ...
- 3,701
3
votes
0
answers
75
views
Infinite stacking of integer quantum Hall systems
Let us consider a (3+1)-dimensional system $\mathcal{H}$ constructed by stacking (2+1)-dimensional integer quantum Hall systems $\mathcal{H}_\text{Hall}$, e.g., $E_8$ bosonic systems (or $\sigma_H=1$ ...
- 813
3
votes
0
answers
911
views
Simple model of edge states for a two-dimensional topological insulator
Quantum spin Hall states or, topological insulators are novel states of matter that have insulating bulk and gapless edge states. Are there any simple models that show these features?
See e.g. the ...
2
votes
0
answers
141
views
Calculating the Hall Conductance using the torus shape for the Magnetic Brillouin zone
Komoto's paper (ANNALS OF PHYSICS 160, 343-354 (1985)) on the calculation of the Hall conductance provides a clear discussion about how calculate the conductance using the torus shaped magnetic ...
2
votes
0
answers
66
views
What's the relation between quanutm hall effect and topological insulator state?
In a recent PRX paper(https://journals.aps.org/prx/abstract/10.1103/PhysRevX.10.011050), I see that in 45nm and 50nm-thick Cd3As2 films, they find quantum hall effect and say that this is because of ...
- 267
2
votes
0
answers
107
views
How does Laughlin argument for hierarchical fractional quantum Hall effect work?
For 1 level and 1 layer $1/q$ FQHE let's say $q=5$ we have the following argument for Laughlin gauge principle. It says that if we adiabatically increase the flux from $0$ to $q\phi_0$ of a corbino ...
- 1,369
2
votes
0
answers
541
views
Hall Conductance and Chern Number Sign Convention
I have a simple question regarding sign conventions pertaining to the Chern number and Hall conductance (and what seems to be inconsistencies in the literature).
In a 2D band insulator, the Chern ...
1
vote
0
answers
42
views
Deriving an alternating expression for Hall Conductivity
I was reading the paper (https://journals.aps.org/prb/abstract/10.1103/PhysRevB.31.3372) in which Thouless and Wu show that the hall conductivity is a topological invariant. My question is about the ...
- 1,778
1
vote
0
answers
99
views
The flat-band basis, Green's function projectors, and TKNN
Bernevig & Hughes' book "Topological Insulators and Topological Superconductors" have a derivation of the TKNN invariant in terms of the finite-temperature Green's function. From the ...
1
vote
0
answers
43
views
Noncontractable loops in the 2D Brilluoin zone and the Chern number
I'm getting quite twisted around trying to figure out what all is quantized exactly in IQH looking at it from the Chern number perspective.
Let's suppose quantum hall on a torus -- I can apply a large ...
- 123
1
vote
0
answers
70
views
Is Hall conductivity time-reversal-odd at finite frequency in a topological system?
In some topological materials, e.g., the quantum (anomalous) Hall state and some related variants, the Hall conductivity $\sigma_{xy}$ is quantized and directly related to the Chern number, which ...
- 3,701