Interplay of filling fraction and coherence in symmetry broken graphene p-n junction

Abstract Graphene p–n junction (PNJ) with co-propagating spin-valley polarized quantum Hall (QH) edges is a promising platform for studying electron interferometry. Though several conductance measurements have been attempted for such PNJs, the edge dynamics of the spin-valley symmetry broken edge states remain unexplored. In this work, we present the measurements of conductance together with shot noise, an ideal tool to unravel the dynamics, at low temperature, in a dual graphite gated hexagonal boron nitride 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. 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 of edge dynamics.

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Analysis of Shot Noise at Finite Temperatures in Fractional Quantum Hall Edge States

Journal of the Physical Society of Japan ◽

10.1143/jpsj.80.073709 ◽

2011 ◽

Vol 80 (7) ◽

pp. 073709 ◽

Cited By ~ 1

Author(s):

Eiki Iyoda ◽

Tatsuya Fujii

Keyword(s):

Shot Noise ◽

Quantum Hall ◽

Edge States ◽

Fractional Quantum ◽

Fractional Quantum Hall

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EDGE EXCITATIONS IN THE FRACTIONAL QUANTUM HALL STATES AT GENERAL FILLING FRACTIONS

Modern Physics Letters B ◽

10.1142/s0217984991000058 ◽

1991 ◽

Vol 05 (01) ◽

pp. 39-46 ◽

Cited By ~ 47

Author(s):

X.G. WEN

Keyword(s):

Quantum Hall ◽

Low Energy ◽

Effective Theory ◽

Edge States ◽

Filling Fraction ◽

Fractional Quantum ◽

Fractional Quantum Hall ◽

Quantum Hall States ◽

Hall States

We propose a scheme to construct the edge states for the Fractional Quantum Hall (FQH) states obtained by the Jain’s scheme. The low energy effective theory of the edge excitations is obtained. We calculate the number of the branches and the electron propagators of the edge states for various FQH states. We demonstrate that two FQH states with the same filling fraction may have different topological orders and may support different edge excitations.

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THEORY OF THE EDGE STATES IN FRACTIONAL QUANTUM HALL EFFECTS

International Journal of Modern Physics B ◽

10.1142/s0217979292000840 ◽

1992 ◽

Vol 06 (10) ◽

pp. 1711-1762 ◽

Cited By ~ 573

Author(s):

XIAO-GANG WEN

Keyword(s):

Quantum Hall ◽

Microscopic Theory ◽

Dynamical Theory ◽

Effective Theory ◽

Edge States ◽

Filling Fraction ◽

Fractional Quantum ◽

Fractional Quantum Hall ◽

Hall Effects ◽

Laughlin States

The dynamical theory of the edge excitations of generic fractional quantum Hall (FQH) states is summarized and expanded. The low energy effective theory of the edge excitations for the most general abelian FQH states (including spin-unpolarized and multi-layer FQH states) and some non-abelian FQH states is derived using several different methods. The propagators of the electrons and the quasiparticles are calculated for the above FQH states. The microscopic theory of the edge excitations for the Laughlin states is also presented. Some simple applications of the edge theory to the transport properties of the FQH states are discussed. In particular, the tunneling between edge states is shown to be a powerful tool to probe the internal topological orders in the FQH states. It can be used to distinguish different FQH states with the same filling fraction and to detect the non-abelian FQH states in experiments.

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Shot-Noise Thermometry of the Quantum Hall Edge States

Physical Review Letters ◽

10.1103/physrevlett.109.246806 ◽

2012 ◽

Vol 109 (24) ◽

Cited By ~ 14

Author(s):

Ivan P. Levkivskyi ◽

Eugene V. Sukhorukov

Keyword(s):

Shot Noise ◽

Quantum Hall ◽

Edge States ◽

Noise Thermometry

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Low temperature mobility improvement in high-mobility strained-Si/Si1-xGex multilayer MOSFETs

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:1998314 ◽

1998 ◽

Vol 08 (PR3) ◽

pp. Pr3-57-Pr3-60

Author(s):

J. B. Roldán ◽

F. Gámiz ◽

J. A. López-Villanueva ◽

J. E. Carceller

Keyword(s):

Low Temperature ◽

High Mobility ◽

Strained Si

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Stable and High-mobility Oxide TFTs using Low-temperature Processed ZTO/IZO Stacked Channels

Proceedings of the International Display Workshops ◽

10.36463/idw.2019.0512 ◽

2019 ◽

pp. 512

Author(s):

Tsubasa Moritsuka ◽

Hiroyuki Uchiyama

Keyword(s):

Low Temperature ◽

High Mobility ◽

Oxide Tfts

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Topological gaps by twisting

Communications Physics ◽

10.1038/s42005-021-00630-3 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Matheus I. N. Rosa ◽

Massimo Ruzzene ◽

Emil Prodan

Keyword(s):

Magnetic Field ◽

Quantum Hall Effect ◽

Twist Angle ◽

Quantum Hall ◽

Topological Phases ◽

Edge States ◽

Layered Systems ◽

Virtual Laboratories ◽

Higher Dimensional ◽

Chern Numbers

AbstractTwisted bilayered systems such as bilayered graphene exhibit remarkable properties such as superconductivity at magic angles and topological insulating phases. For generic twist angles, the bilayers are truly quasiperiodic, a fact that is often overlooked and that has consequences which are largely unexplored. Herein, we uncover that twisted n-layers host intrinsic higher dimensional topological phases, and that those characterized by second Chern numbers can be found in twisted bi-layers. We employ phononic lattices with interactions modulated by a second twisted lattice and reveal Hofstadter-like spectral butterflies in terms of the twist angle, which acts as a pseudo magnetic field. The phason provided by the sliding of the layers lives on 2n-tori and can be used to access and manipulate the edge states. Our work demonstrates how multi-layered systems are virtual laboratories for studying the physics of higher dimensional quantum Hall effect, and can be employed to engineer topological pumps via simple twisting and sliding.

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Edge channels of broken-symmetry quantum Hall states in graphene visualized by atomic force microscopy

Nature Communications ◽

10.1038/s41467-021-22886-7 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Sungmin Kim ◽

Johannes Schwenk ◽

Daniel Walkup ◽

Yihang Zeng ◽

Fereshte Ghahari ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Chemical Potential ◽

Quantum Hall ◽

Broken Symmetry ◽

Topological Order ◽

Edge States ◽

Force Microscopy ◽

Atomic Force ◽

Intimate Relation ◽

Boundary Measurements

AbstractThe quantum Hall (QH) effect, a topologically non-trivial quantum phase, expanded the concept of topological order in physics bringing into focus the intimate relation between the “bulk” topology and the edge states. The QH effect in graphene is distinguished by its four-fold degenerate zero energy Landau level (zLL), where the symmetry is broken by electron interactions on top of lattice-scale potentials. However, the broken-symmetry edge states have eluded spatial measurements. In this article, we spatially map the quantum Hall broken-symmetry edge states comprising the graphene zLL at integer filling factors of $${{\nu }}={{0}},\pm {{1}}$$ ν = 0 , ± 1 across the quantum Hall edge boundary using high-resolution atomic force microscopy (AFM) and show a gapped ground state proceeding from the bulk through to the QH edge boundary. Measurements of the chemical potential resolve the energies of the four-fold degenerate zLL as a function of magnetic field and show the interplay of the moiré superlattice potential of the graphene/boron nitride system and spin/valley symmetry-breaking effects in large magnetic fields.

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