# Valley-isospin dependence of the quantum Hall effect in a graphene p − n junction

@article{Tworzydo2007ValleyisospinDO, title={Valley-isospin dependence of the quantum Hall effect in a graphene p − n junction}, author={Jakub Tworzydło and Izak M. Snyman and A. Akhmerov and C. W. J. Beenakker}, journal={Physical Review B}, year={2007}, volume={76}, pages={035411} }

We calculate the conductance $G$ of a bipolar junction in a graphene nanoribbon, in the high-magnetic-field regime where the Hall conductance in the $p$-doped and $n$-doped regions is $2{e}^{2}∕h$. In the absence of intervalley scattering, the result $G=({e}^{2}∕h)(1\ensuremath{-}\mathrm{cos}\phantom{\rule{0.2em}{0ex}}\ensuremath{\Phi})$ depends only on the angle $\ensuremath{\Phi}$ between the valley isospins ($=\text{Bloch}$ vectors representing the spinor of the valley polarization) at the…

## 49 Citations

Ballistic-Ohmic quantum Hall plateau transition in a graphene p − n junction

- Physics
- 2009

Recent quantum Hall experiments conducted on disordered graphene $p\text{\ensuremath{-}}n$ junction provide evidence that the junction resistance could be described by a simple Ohmic sum of the $n$…

Valley isospin of interface states in a graphene
pn
junction in the quantum Hall regime

- PhysicsPhysical Review B
- 2019

In the presence of crossed electric and magnetic fields, a graphene ribbon has chiral states running along sample edges and along boundaries between $p$-doped and $n$-doped regions. We here consider…

Graphene
n−p
junctions in the quantum Hall regime: Numerical study of incoherent scattering effects

- PhysicsPhysical Review B
- 2018

We investigate electronic transport through a graphene $n$-$p$ junction in the quantum Hall effect regime at high perpendicular magnetic field, when the filling factors in the $n$-doped and $p$-doped…

Giant Valley-Isospin Conductance Oscillations in Ballistic Graphene.

- PhysicsNano letters
- 2017

P-n junctions in encapsulated graphene with a movable p-n interface are investigated with large quantum conductance oscillations on the order of e2/h which solely depend on the p- n junction position providing the first signature of isospin-defined conductance.

Dependence of the NS conductance on the valley polarisation of edge states in graphene

- Physics
- 2019

The edge states in ﬁnite quantum Hall graphene have previously been shown to be valley polarised for zigzag and armchair edges. Assuming that the valley isospin is also conserved at a smooth…

Theory of the valley-valve effect in graphene nanoribbons

- Physics
- 2008

A potential step in a graphene nanoribbon with zigzag edges is shown to be an intrinsic source of intervalley scattering -- no matter how smooth the step is on the scale of the lattice constant a.…

Disorder effects in the quantum Hall effect of graphene p-n junctions

- Physics
- 2008

The quantum Hall effect in graphene $p\text{\ensuremath{-}}n$ junctions is studied numerically with emphasis on the effect of disorder at the interface of two adjacent regions. Conductance plateaus…

Influence of Coupling Strength Between a Magnetic Quantum Dot and Quantum Hall Edge Channels on Valley-isospin-dependent Dirac Fermion Transport

- Physics
- 2020

We investigate Dirac fermion transport through opposite quantum Hall edge channels in armchair graphene nanoribbons where a magnetic quantum dot (MQD) is placed between the edges. The resulting…

Circular n-p Junctions in Graphene Nanoribbons

- Physics
- 2018

A characteristic feature of graphene as the Dirac conductor is that one can introduce doping by external voltages, so that the n-p junction can be defined and controlled by gating. The electrostatic…

Thermopower and conductance for a graphene p–n junction

- PhysicsJournal of physics. Condensed matter : an Institute of Physics journal
- 2012

The thermopower and conductance in a zigzag graphene p–n junction are studied by using the nonequilibrium Green’s function method combined with the tight-binding Hamiltonian. Our results show that…

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With hindsight, the same analogy can be noted between the phenomena of negative refraction of Ref. [6] and Andreev retroreflection of Ref

3) is invariant under the transformation ν → −ν, θ → θ + π. This freedom is used to choose the sign of ν such that the electron-like edge channel has isospin +ν