Ferroelectric control of valleytronic nonvolatile storage in HfCl2/Sc2CO2 heterostructure
Zhou Cui,
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Xunkai Duan,
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Jiansen Wen
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et al.
Applied Physics Letters,
Journal Year:
2025,
Volume and Issue:
126(12)
Published: March 1, 2025
Valleytronics,
utilizing
the
valley
degree
of
freedom
in
electrons,
has
potential
for
advancing
next-generation
nonvolatile
storage.
However,
practical
implementation
remains
challenging
due
to
limited
control
over
valleytronic
properties.
Here,
we
propose
ferroelectric
HfCl2/Sc2CO2
van
der
Waals
heterostructure
as
a
platform
overcome
these
limitations,
enabling
tunable
and
behaviors.
Our
findings
show
that
electric
polarization
state
Sc2CO2
monolayer
governs
electronic
properties
heterostructures.
Positive
induces
direct
gap
at
valleys,
functionality
excitation
readout
via
circularly
polarized
light,
while
negative
results
an
indirect-gap,
suppressing
behavior.
Moreover,
our
transport
simulations
further
demonstrate
polarization-dependent
p-i-n
junction
with
8
nm
possesses
maximum
tunnel
electroresistance
(TER)
ratio
1.60
×
108%
bias
0.5
eV.
These
provide
insights
into
ferroelectric-controlled
transitions
position
promising
candidate
energy-efficient
memory
storage
applications.
Language: Английский
High Throughput Discovery of 2D Ferromagnetic and Multiferroic Transition Metal Oxyhalides and Nitrogen Halides
Research Square (Research Square),
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 11, 2025
Abstract
Two-dimensional
(2D)
transition
metal
oxyhalides
and
nitrogen-halides
(TMBXs,
where
TM
=
metal,
B
O-group
N-group
elements,
X
halogen)
have
emerged
as
promising
candidates
for
exploring
multiferroic
orders
spintronic
applications.
In
this
study,
we
conduct
a
systematic
first-principles
high-throughput
screening
combined
with
machine
learning
to
identify
novel
2D
ferromagnetic
materials
within
TMBX
family.
From
comprehensive
dataset
comprising
672
monolayers,
78
systems,
of
which
38
exhibit
high
Curie
temperatures
(TC
≥
200
K),
significantly
expanding
the
known
library
magnetic
materials.
A
model
is
developed
elucidate
key
factors
governing
ferromagnetism,
revealing
that
second-nearest
neighbor
exchange
interaction
(J2)
plays
dominant
role
in
determining
TC.
Furthermore,
discover
seven
ferromagnetic-ferroelectric
unique
polarization
switching
pathways.
Notably,
spin
transport
simulations
using
nonequilibrium
Green's
function
formalism
demonstrate
exceptional
filtering
capabilities
(~
100
%)
giant
bias-dependent
tunneling
magnetoresistance
(>
105
%).
These
findings
deepen
fundamental
understanding
multiferroics
establish
solid
platform
future
experimental
exploration
development
next-generation
devices.
Language: Английский
Large and Tunable Electron-Depletion-Based Voltage-Controlled Magnetic Anisotropy in the CoFeB/MgO System via Work-Function-Engineered PtxW1–x Underlayers
Yu‐Chia Chen,
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T. Peterson,
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Qi Jia
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et al.
ACS Nano,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 14, 2025
Voltage-Controlled
Magnetic
Anisotropy
(VCMA)
effect
is
a
promising
strategy
for
reducing
energy
consumption
in
Random-Access
Memory
(MRAM)
embedded
applications.
However,
the
low
efficiency
of
VCMA
poses
challenges
CoFeB/MgO-based
MRAM.
Although
significant
coefficients
have
been
predicted
based
on
electron
depletion
(ED)
orbital
population
model
Fe/MgO
interfaces,
experimental
validation
remains
limited.
Here,
we
demonstrate
an
effective
and
industry-compatible
approach
to
achieving
electrical-field
tunable
interfacial
perpendicular
magnetic
anisotropy
(PMA)
enhanced
coefficient
by
synthesizing
W-based
metallic
alloy
underlayers
with
varying
Pt
concentrations,
leveraging
Pt's
high
work
function
strong
electronegativity.
Compared
pure
W
control
devices,
highest
concentration
achieves
enhancement
approximately
eight
times
greater.
Additionally,
Fe
2p3/2
2p1/2
orbitals
at
CoFeB/MgO
interface
observed
through
binding
shifts.
High-resolution
X-ray
photoelectron
spectroscopy
(HR-XPS)
confirms
these
shifts
as
increased
energies,
indicating
reduced
density
interface.
These
findings
suggest
that
MRAM
devices
can
be
controlling
Fermi
surface
under
thermal
equilibrium.
Language: Английский
Giant Nonvolatile Multistate Resistance with Fully Magnetically Controlled van der Waals Multiferroic Tunnel Junctions
Zhi Yan,
No information about this author
Xujin Zhang,
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Jianhua Xiao
No information about this author
et al.
Nano Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 15, 2025
Ferroelectric
polarization
switching
in
electrically
controlled
van
der
Waals
multiferroic
tunnel
junctions
(vdW-MFTJs)
causes
atomic
migration,
compromising
device
stability
and
fatigue
resistance.
Here,
we
propose
fully
magnetically
vdW-MFTJs
based
on
a
CrBr3/MnPSe3/CrBr3
vertical
heterostructure,
achieving
ferroelectric
reversal
without
migration.
First-principles
calculations
reveal
that
integrating
PtTe2/alkali-metal
(Li/Na/K)-doped/intercalated
CrBr3
electrodes
enables
exceptional
performance,
with
maximum
tunneling
magnetoresistance
(TMR)
of
8.1
×
105%
electroresistance
(TER)
2499%.
Applying
an
external
bias
voltage
enhances
the
TMR
to
3.6
107%
TER
9990%.
A
pronounced
negative
differential
resistance
(NDR)
effect
is
observed
record
peak-to-valley
ratio
(PVR)
9.55
109%
for
junctions.
The
spin-filtering
channels
are
flexibly
by
magnetization
direction
magnetic
free
layer,
perfect
over
broad
range.
This
work
paves
way
experimental
exploration
vdW-MFTJs.
Language: Английский