We
develop
a
systematic
theory
for
excitons
subject
to
Fermi-Hubbard
physics
in
moir\'e
twisted
transition
metal
dichalcogenides
(TMDs).
Specifically,
we
consider
from
two
bands
with
Mott-insulating
valence
band
sustaining
${120}^{\ensuremath{\circ}}$
spin
order.
These
``Mott-moir\'e
excitons,''
which
are
achievable
TMD
heterobilayers,
bound
states
of
magnetic
polaron
the
and
free
electron
conduction
band.
find
significantly
narrower
exciton
bandwidths
presence
Hubbard
physics,
serving
as
potential
experimental
signature
strong
correlations.
also
demonstrate
high
tunability
Mott-moir\'e
through
dependence
their
binding
energies,
diameters,
on
period.
In
addition,
study
between
charges
outside
strongly
correlated
that
these
well
exhibit
signatures
correlation.
Our
work
provides
guidelines
future
exploration
triangular
systems
such
heterobilayers.
Physical Review Letters,
Journal Year:
2024,
Volume and Issue:
132(7)
Published: Feb. 16, 2024
Laser
modulation
spectroscopy
on
a
MoSe${}_{2}$/WS${}_{2}$
heterostructure
shows
an
intricate
interplay
of
both
intra-
and
interlayer
moir\'e
excitons
allows
to
determine
unambiguously
the
nature
observed
optical
resonances.
Physical Review Letters,
Journal Year:
2024,
Volume and Issue:
132(18)
Published: April 30, 2024
Optical
excitations
in
moiré
transition
metal
dichalcogenide
bilayers
lead
to
the
creation
of
excitons,
as
electron-hole
bound
states,
that
are
generically
considered
within
a
Bose-Hubbard
framework.Here,
we
demonstrate
these
composite
particles
obey
an
angular
momentum
commutation
relation
is
generally
non-bosonic.This
emergent
spin
description
excitons
indicates
limitation
their
occupancy
on
each
site,
which
substantial
weak
binding
regime.The
effective
exciton
theory
accordingly
Hamiltonian,
further
becomes
Hubbard
model
bosons
subject
constraint
after
Holstein-Primakoff
transformation.We
apply
our
three
commonly
studied
(MoSe2/WSe2,
WSe2/WS2,
and
WSe2/MoS2)
show
relevant
parameter
regimes
allowed
occupancies
never
exceed
excitons.Our
systematic
provides
guidelines
for
future
research
many-body
physics
excitons.
ACS Nano,
Journal Year:
2024,
Volume and Issue:
18(28), P. 18202 - 18210
Published: July 1, 2024
Stacking
van
der
Waals
crystals
allows
for
the
on-demand
creation
of
a
periodic
potential
landscape
to
tailor
transport
quasiparticle
excitations.
We
investigate
diffusion
photoexcited
electron–hole
pairs,
or
excitons,
at
interface
WS2/WSe2
heterostructure
over
wide
range
temperatures.
observe
appearance
distinct
interlayer
excitons
parallel
and
antiparallel
stacking
track
their
through
spatially
temporally
resolved
photoluminescence
spectroscopy
from
30
250
K.
While
measured
exciton
diffusivity
decreases
with
temperature,
it
surprisingly
plateaus
below
90
Our
observations
cannot
be
explained
by
classical
models
like
hopping
in
moiré
potential.
A
combination
ab
initio
theory
molecular
dynamics
simulations
suggests
that
low-energy
phonons
arising
mismatched
lattices
heterostructures,
also
known
as
phasons,
play
key
role
describing
understanding
this
anomalous
behavior
diffusion.
indicate
is
dynamic
down
very
low
temperatures
phason
modes
can
enable
efficient
energy
form
excitons.
Nano Letters,
Journal Year:
2023,
Volume and Issue:
23(10), P. 4160 - 4166
Published: May 4, 2023
Vertical
van
der
Waals
heterostructures
of
semiconducting
transition
metal
dichalcogenides
realize
moiré
systems
with
rich
correlated
electron
phases
and
exciton
phenomena.
For
material
combinations
small
lattice
mismatch
twist
angles
as
in
MoSe2-WSe2,
however,
reconstruction
eliminates
the
canonical
pattern
instead
gives
rise
to
arrays
periodically
reconstructed
nanoscale
domains
mesoscopically
extended
areas
one
atomic
registry.
Here,
we
elucidate
role
MoSe2-WSe2
synthesized
by
chemical
vapor
deposition.
With
complementary
imaging
down
scale,
simulations,
optical
spectroscopy
methods,
identify
coexistence
moiré-type
cores
moiré-free
regions
heterostacks
parallel
antiparallel
alignment.
Our
work
highlights
potential
deposition
for
applications
requiring
laterally
heterosystems
registry
or
exciton-confining
heterostack
arrays.
We
develop
a
systematic
theory
for
excitons
subject
to
Fermi-Hubbard
physics
in
moir\'e
twisted
transition
metal
dichalcogenides
(TMDs).
Specifically,
we
consider
from
two
bands
with
Mott-insulating
valence
band
sustaining
${120}^{\ensuremath{\circ}}$
spin
order.
These
``Mott-moir\'e
excitons,''
which
are
achievable
TMD
heterobilayers,
bound
states
of
magnetic
polaron
the
and
free
electron
conduction
band.
find
significantly
narrower
exciton
bandwidths
presence
Hubbard
physics,
serving
as
potential
experimental
signature
strong
correlations.
also
demonstrate
high
tunability
Mott-moir\'e
through
dependence
their
binding
energies,
diameters,
on
period.
In
addition,
study
between
charges
outside
strongly
correlated
that
these
well
exhibit
signatures
correlation.
Our
work
provides
guidelines
future
exploration
triangular
systems
such
heterobilayers.
