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Effects of dynamical screening on the BCS-BEC crossover in double bilayer graphene : Density functional theory for exciton bilayers

Nilsson, F. LU and Aryasetiawan, F. LU (2021) In Physical Review Materials 5(5).
Abstract

We derive a gap equation for bilayer excitonic systems based on density functional theory and benchmark our results against quantum Monte Carlo simulations and recent experiments on double bilayer graphene. The gap equation has a mean-field form but includes a consistent treatment of dynamical screening. We show that the gap survives at much higher densities than previously thought from mean-field estimates which gives strong indications that the double-bilayer graphene systems at zero magnetic field can be used as model systems to investigate the BCS-BEC crossover. Furthermore, we show that Josephson-like transfer of pairs can be substantial for small band gaps and densities.

Please use this url to cite or link to this publication:
author
and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Materials
volume
5
issue
5
article number
L050801
publisher
American Physical Society
external identifiers
  • scopus:85106349586
ISSN
2475-9953
DOI
10.1103/PhysRevMaterials.5.L050801
language
English
LU publication?
yes
id
acd32400-2588-4725-aabc-4fe28fd02b66
date added to LUP
2022-03-03 12:51:05
date last changed
2022-04-18 23:36:25
@article{acd32400-2588-4725-aabc-4fe28fd02b66,
  abstract     = {{<p>We derive a gap equation for bilayer excitonic systems based on density functional theory and benchmark our results against quantum Monte Carlo simulations and recent experiments on double bilayer graphene. The gap equation has a mean-field form but includes a consistent treatment of dynamical screening. We show that the gap survives at much higher densities than previously thought from mean-field estimates which gives strong indications that the double-bilayer graphene systems at zero magnetic field can be used as model systems to investigate the BCS-BEC crossover. Furthermore, we show that Josephson-like transfer of pairs can be substantial for small band gaps and densities.</p>}},
  author       = {{Nilsson, F. and Aryasetiawan, F.}},
  issn         = {{2475-9953}},
  language     = {{eng}},
  month        = {{05}},
  number       = {{5}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Materials}},
  title        = {{Effects of dynamical screening on the BCS-BEC crossover in double bilayer graphene : Density functional theory for exciton bilayers}},
  url          = {{http://dx.doi.org/10.1103/PhysRevMaterials.5.L050801}},
  doi          = {{10.1103/PhysRevMaterials.5.L050801}},
  volume       = {{5}},
  year         = {{2021}},
}