Interplay of filling fraction and coherence in symmetry broken graphene p-n junction
arXiv:2010.00496 · doi:10.1038/s42005-020-00434-x
Abstract
The coherence of quantum Hall (QH) edges play the deciding factor in demonstrating an electron interferometer, which has potential to realize a topological qubit. A Graphene p-n junction (PNJ) with co-propagating spin and valley polarized QH edges is a promising platform for studying an electron interferometer. However, though a few experiments have been attempted for such PNJ via conductance measurements, the edge dynamics (coherent or incoherent) of QH edges at a PNJ, where either spin or valley symmetry or both are broken, remain unexplored. In this work, we have carried out the measurements of conductance together with shot noise, an ideal tool to unravel the dynamics, at low temperature (~ 10mK) in a dual graphite gated hexagonal boron nitride (hBN) encapsulated high mobility graphene device. The conductance data show that the symmetry broken QH edges at the PNJ follow spin selective equilibration. The shot noise results as a function of both p and n side filling factors reveal the unique dependence of the scattering mechanism with filling factors. Remarkably, the scattering is found to be fully tunable from incoherent to coherent regime with the increasing number of QH edges at the PNJ, shedding crucial insights into graphene based electron interferometer.
References in corpus (20)
- The electronic properties of graphene
- Landau Level Splitting in Graphene in High Magnetic Fields
- Spin Filtered Edge States and Quantum Hall Effect in Graphene
- Electronic transport and quantum Hall effect in bipolar graphene p-n-p junction
- Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride
- Quantized Transport in Graphene p-n Junctions in Magnetic Field
- Disorder-induced enhancement of transport through graphene p-n junctions
- Tuning Energy Relaxation along Quantum Hall Channels
- Aharonov-Bohm interference of fractional quantum Hall edge modes
- Snake Trajectories in Ultraclean Graphene p-n Junctions
- Detecting non-Abelian Statistics with Electronic Mach-Zehnder Interferometer
- Disorder Effects in the Quantum Hall Effect of Graphene p-n Junctions
- Gate-Defined Graphene Quantum Point Contact in the Quantum Hall Regime
- Giant valley-isospin conductance oscillations in ballistic graphene
- Theory of Landau level mixing in heavily graded graphene p-n junctions
- Interplay between snake and quantum edge states in a graphene Hall bar with a pn-junction
- Imaging snake orbits at graphene n-p junctions
- Graphene pn-junction in a quantizing magnetic field: Conductance at intermediate disorder strength
- Enhanced shot noise at bilayer graphene -- superconductor junction
- Strong equilibration of Landau levels edge-states at the graphene edge