arXiv (Cornell University),
Journal Year:
2023,
Volume and Issue:
unknown
Published: Jan. 1, 2023
We
show
that
hexagonal
boron
nitride
(hBN),
a
two-dimensional
insulator,
when
subjected
to
an
external
superlattice
potential
forms
new
paradigm
for
electrostatically
tunable
excitons
in
the
near-
and
mid-ultraviolet
(UV).
The
imposed
has
three
consequences:
(i)
it
renormalizes
effective
mass
tensor,
leading
anisotropic
masses;
(ii)
band
gap,
eventually
reducing
it;
(iii)
reduces
exciton
binding
energies.
All
these
consequences
depend
on
single
dimensionless
parameter,
which
includes
product
of
strength
with
its
period.
In
addition
excitonic
energy
levels,
we
compute
optical
conductivity
along
two
orthogonal
directions,
from
absorption
spectrum.
results
latter
our
system
is
able
mimic
grid
polarizer.
These
characteristics
make
one-dimensional
hBN
superlattices
viable
unexplored
platform
fine-tuned
polaritonics
UV
visible
spectral
range.
Chemical Reviews,
Journal Year:
2024,
Volume and Issue:
124(4), P. 1992 - 2079
Published: Feb. 9, 2024
Twisted
van
der
Waals
(vdW)
quantum
materials
have
emerged
as
a
rapidly
developing
field
of
two-dimensional
(2D)
semiconductors.
These
establish
new
central
research
area
and
provide
promising
platform
for
studying
phenomena
investigating
the
engineering
novel
optoelectronic
properties
such
single
photon
emission,
nonlinear
optical
response,
magnon
physics,
topological
superconductivity.
captivating
electronic
result
from,
can
be
tailored
by,
interlayer
coupling
using
moiré
patterns
formed
by
vertically
stacking
atomic
layers
with
controlled
angle
misorientation
or
lattice
mismatch.
Their
outstanding
high
degree
tunability
position
them
compelling
building
blocks
both
compact
quantum-enabled
devices
classical
optoelectronics.
This
paper
offers
comprehensive
review
recent
advancements
in
understanding
manipulation
twisted
structures
presents
survey
state-of-the-art
on
superlattices,
encompassing
interdisciplinary
interests.
It
delves
into
fundamental
theories,
synthesis
fabrication,
visualization
techniques,
wide
range
physical
exhibited
these
structures,
focus
their
potential
practical
device
integration
applications
ranging
from
information
to
biosensors,
including
optoelectronics
modulators,
light
emitting
diodes,
lasers,
photodetectors.
highlights
unique
ability
superlattices
connect
multiple
disciplines,
covering
chemistry,
electronics,
optics,
photonics,
magnetism,
physics.
provides
valuable
resource
researchers
interested
shedding
characteristics
transformative
various
fields.
Physical Review Letters,
Journal Year:
2025,
Volume and Issue:
134(8)
Published: Feb. 26, 2025
The
moir\'e
superlattices
attract
growing
interest
for
holding
exotic
physics
due
to
their
fascinating
properties
from
electronics
photonics.
Much
attention
has
been
focused
on
the
localization
effect
waves
in
flat
band
regime
or
delocalization
strongly
dispersive
feature.
Here,
we
study
weakly
between
two
above
scenarios
a
one-dimensional
synthetic
frequency
superlattice
and
observe
wave
packet
distributions
therein
toward
novel
comb
generation.
Mode
spacing
spectral
is
reduced
compared
free
range
of
individual
rings
mode
couplings
unequal
sublattice
periods
lattice.
We
unveil
that
optimal
compact
generation
occurs
simultaneously
uniform
power
distribution
broad
spanning
our
experiment,
benefiting
interplay
flatness
uniformity
distribution.
Our
results
fundamental
dimension
also
show
new
way
future
on-chip
devices
with
small
footprint
size.
Nano Letters,
Journal Year:
2024,
Volume and Issue:
24(9), P. 2773 - 2781
Published: Jan. 29, 2024
Transition
metal
dichalcogenide
(TMD)
heterobilayers
have
emerged
as
a
promising
platform
for
exploring
solid-state
quantum
simulators
and
many-body
phenomena.
Their
type
II
band
alignment,
combined
with
the
moiré
superlattice,
inevitably
leads
to
nontrivial
exciton
interactions
dynamics.
Here,
we
unveil
distinct
Auger
annihilation
processes
delocalized
interlayer
excitons
in
WS2/WSe2
heterobilayers.
By
fitting
characteristic
efficiency
droop
bimolecular
recombination
rate,
quantitatively
determine
an
ultralow
coefficient
of
1.3
×
10–5
cm2
s–1,
which
is
>100-fold
smaller
than
that
TMD
monolayers.
In
addition,
reveal
selective
upconversion
into
WSe2
layer,
highlights
significance
intralayer
electron
Coulomb
dictating
microscopic
scattering
pathways.
The
arising
from
spatial
electron–hole
separation
important
implications
while
endowing
their
strongly
correlated
states
unique
layer
degrees
freedom.
Frontiers of Physics,
Journal Year:
2024,
Volume and Issue:
19(4)
Published: March 1, 2024
Abstract
Heterostructures
composed
of
two-dimensional
van
der
Waals
(vdW)
materials
allow
highly
controllable
stacking,
where
interlayer
twist
angles
introduce
a
continuous
degree
freedom
to
alter
the
electronic
band
structures
and
excitonic
physics.
Motivated
by
discovery
Mott
insulating
states
superconductivity
in
magic-angle
bilayer
graphene,
emerging
research
fields
“twistronics”
moiré
physics
have
aroused
great
academic
interests
engineering
optoelectronic
properties
exploration
new
quantum
phenomena,
which
superlattice
provides
pathway
for
realization
artificial
crystals.
Here
we
systematically
summarize
current
achievements
twistronics
physics,
with
emphasis
on
roles
lattice
rotational
mismatches
atomic
registries.
Firstly,
review
effects
photonic
particularly
exciton
such
as
dipole
moment
spin-valley
polarization,
through
interactions
structures.
We
also
discuss
dynamics
vdW
heterostructures
different
angles,
like
formation,
transport
relaxation
processes,
whose
mechanisms
are
complicated
still
need
further
investigations.
Subsequently,
theoretical
analysis
experimental
observations
modulated
excitons.
Various
exotic
shown,
including
periodic
potential,
miniband,
varying
wave
function
symmetry,
result
localization,
emergent
peaks
spatially
alternating
optical
selection
rule.
expanded
systems
external
modulation
factors
electric
field,
doping
strain,
showing
that
is
promising
platform
high
tunability
applications
in-depth
study
frontier
Lastly,
focus
rapidly
developing
field
correlated
electron
based
system,
potentially
related
phenomena.
2D Materials,
Journal Year:
2024,
Volume and Issue:
11(2), P. 025030 - 025030
Published: March 19, 2024
Atomically
thin
heterostructures
formed
by
twisted
transition
metal
dichalcogenides
can
be
used
to
create
periodic
moir\'e
patterns.
The
emerging
potential
trap
interlayer
excitons
into
arrays
of
strongly
interacting
bosons,
which
form
a
unique
platform
study
correlated
many-body
states.
In
order
and
manipulate
these
exotic
phases
matter,
microscopic
understanding
exciton-exciton
interactions
their
manifestation
in
systems
becomes
indispensable.
Recent
density-dependent
photoluminescence
(PL)
measurements
have
revealed
novel
spectral
features
indicating
the
formation
trapped
multi-exciton
states
providing
important
information
about
interaction
strength.
this
work,
we
develop
theory
model
PL
spectrum
complexes
focusing
on
emission
from
single-
biexcitons.
Based
an
excitonic
Hamiltonian
determine
properties
biexcitons
as
function
twist
angle
use
insights
predict
luminescence
for
different
densities.
We
demonstrate
how
side
peaks
resulting
transitions
excited
life
time
analysis
utilized
indicators
provide
crucial
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: Oct. 9, 2024
Moiré
superlattices
in
van
der
Waals
heterostructures
represent
a
highly
tunable
quantum
system,
attracting
substantial
interest
both
many-body
physics
and
device
applications.
However,
the
influence
of
moiré
potential
on
light-matter
interactions
at
room
temperature
has
remained
largely
unexplored.
In
our
study,
we
demonstrate
that
MoS
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: Feb. 5, 2024
Abstract
Moiré
excitons
(MXs)
are
electron-hole
pairs
localised
by
the
periodic
(moiré)
potential
forming
in
two-dimensional
heterostructures
(HSs).
MXs
can
be
exploited,
e.g.,
for
creating
nanoscale-ordered
quantum
emitters
and
achieving
or
probing
strongly
correlated
electronic
phases
at
relatively
high
temperatures.
Here,
we
studied
exciton
properties
of
WSe
2
/MoSe
HSs
from
T
=
6
K
to
room
temperature
using
time-resolved
continuous-wave
micro-photoluminescence
also
under
a
magnetic
field.
The
dynamics
emission
lineshape
evolution
with
show
clear
signatures
that
de-trap
moiré
turn
into
free
interlayer
(IXs)
temperatures
above
100
K.
MX-to-IX
transition
is
apparent
moment
reversing
its
sign
when
not
capable
localising
elevated
Concomitantly,
formation
decay
times
reduce
drastically.
Thus,
our
findings
establish
conditions
truly
confined
nature
states
superlattice
increasing
photo-generated
carrier
density.
