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Title: Local, global, and nonlinear screening in twisted double-layer graphene

One-atom-thick crystalline layers and their vertical heterostructures carry the promise of designer electronic materials that are unattainable by standard growth techniques. To realize their potential it is necessary to isolate them from environmental disturbances, in particular those introduced by the substrate. However, finding and characterizing suitable substrates, and minimizing the random potential fluctuations they introduce, has been a persistent challenge in this emerging field. In this paper, we show that Landau-level (LL) spectroscopy offers the unique capability to quantify both the reduction of the quasiparticles’ lifetime and the long-range inhomogeneity due to random potential fluctuations. Harnessing this technique together with direct scanning tunneling microscopy and numerical simulations we demonstrate that the insertion of a graphene buffer layer with a large twist angle is a very effective method to shield a 2D system from substrate interference that has the additional desirable property of preserving the electronic structure of the system under study. Finally, we further show that owing to its remarkable nonlinear screening capability a single graphene buffer layer provides better shielding than either increasing the distance to the substrate or doubling the carrier density and reduces the amplitude of the potential fluctuations in graphene to values even lower than themore » ones in AB-stacked bilayer graphene.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [4] ;  [2] ;  [1]
  1. The State Univ. of New Jersey, Piscataway, NJ (United States)
  2. College of William and Mary, Williamsburg, VA (United States)
  3. The State Univ. of New Jersey, Piscataway, NJ (United States); Ottawa Univ., Ottawa, ON (Canada)
  4. National Institute for Materials Science, Tsukuba (Japan)
Publication Date:
OSTI Identifier:
1255459
Grant/Contract Number:
FG02-99ER45742
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 24; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Rutgers Univ., New Brunswick, NJ (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; graphene; STM; screening; Landau-level spectroscopy