Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gate tunable topological flat bands in twisted monolayer-bilayer
  graphene   We investigate the band structure of twisted monolayer-bilayer graphene
(tMBG), or twisted graphene on bilayer graphene (tGBG), as a function of twist
angles and perpendicular electric fields in search of optimum conditions for
achieving isolated nearly flat bands. Narrow bandwidths comparable or smaller
than the effective Coulomb energies satisfying $U_{\textrm{eff}} /W \gtrsim 1$
are expected for twist angles in the range of $0.3^{\circ} \sim 1.5^{\circ}$,
more specifically in islands around $\theta \sim 0.5^{\circ}, \, 0.85^{\circ},
\,1.3^{\circ}$ for appropriate perpendicular electric field magnitudes and
directions. The valley Chern numbers of the electron-hole asymmetric bands
depend intrinsically on the details of the hopping terms in the bilayer
graphene, and extrinsically on factors like electric fields or average
staggered potentials in the graphene layer aligned with the contacting
hexagonal boron nitride substrate. This tunability of the band isolation,
bandwidth, and valley Chern numbers makes of tMBG a more versatile system than
twisted bilayer graphene for finding nearly flat bands prone to strong
correlations.

1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys