Long-range ballistic transport of Brown-Zak fermions in graphene superlattices
Julien Barrier,Piranavan Kumaravadivel,Roshan Krishna Kumar,Leonid Ponomarenko,Leonid Ponomarenko,Na Xin,Matthew Holwill,Ciaran Mullan,Minsoo Kim,Roman V. Gorbachev,Michael Thompson,Jonathan Prance,T. Taniguchi,Kenji Watanabe,Irina V. Grigorieva,Kostya S. Novoselov,Artem Mishchenko,Vladimir I. Fal'ko,Andre K. Geim,A. I. Berdyugin +19 more
TLDR
In this paper, it was shown that Brown-Zak minibands are 4q times degenerate and all the degeneracies (spin, valley and mini-valley) can be lifted by exchange interactions below 1'K.Abstract:
In quantizing magnetic fields, graphene superlattices exhibit a complex fractal spectrum often referred to as the Hofstadter butterfly. It can be viewed as a collection of Landau levels that arise from quantization of Brown-Zak minibands recurring at rational (p/q) fractions of the magnetic flux quantum per superlattice unit cell. Here we show that, in graphene-on-boron-nitride superlattices, Brown-Zak fermions can exhibit mobilities above 106 cm2 V−1 s−1 and the mean free path exceeding several micrometers. The exceptional quality of our devices allows us to show that Brown-Zak minibands are 4q times degenerate and all the degeneracies (spin, valley and mini-valley) can be lifted by exchange interactions below 1 K. We also found negative bend resistance at 1/q fractions for electrical probes placed as far as several micrometers apart. The latter observation highlights the fact that Brown-Zak fermions are Bloch quasiparticles propagating in high fields along straight trajectories, just like electrons in zero field. Here, the authors show that Brown-Zak fermions in graphene-on-boron-nitride superlattices exhibit mobilities above 106 cm2/V s and micrometer scale ballistic transport.read more
Citations
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Posted Content
Out-of-equilibrium criticalities in graphene superlattices
A. I. Berdyugin,Na Xin,Haoyang Gao,Sergey Slizovskiy,Zhiyu Dong,Shubhadeep Bhattacharjee,Piranavan Kumaravadivel,Shuigang Xu,Leonid Ponomarenko,Matthew Holwill,Denis A. Bandurin,Minsoo Kim,Yang Cao,Mark Greenaway,Kostya S. Novoselov,Irina V. Grigorieva,Kazuyuki Watanabe,T. Taniguchi,Vladimir I. Fal'ko,Leonid Levitov,R. Krishna Kumar,A. K. Geim +21 more
TL;DR: In this article, the authors describe a very different regime in which carrier distribution in graphene and its superlattices is shifted so far from equilibrium that the filled bands start playing an essential role, leading to a critical current behavior.
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Synthesis of graphene nanoplatelets/polythiophene nanocomposites With Enhanced Photocatalytic Degradation of Bromophenol Blue and Antibacterial Properties
TL;DR: In this paper, the photocatalytic degradation of bromo phenol blue (BPB) and pathogen control was investigated using polythiophene (PTh) and graphene nanoplatelets (GNPs) nanocomposites.
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