Transcript (pptx)

Artificial Low Dimensional Materials
Han Woong Yeom
Contents
I.
II.
Physics Issues
Key Ideas
III. Executive Plans
IV. Current Research
I. Physics Issues
Physics of low dimensional systems
Organic conductors
1970
Quantum Hall effect
1980
High temperature
superconductor
canbon nanotube
1990
2000
graphene
topologocal
insulator
2010
What for next decade ?
2020
Old, but unsolved, grand problem
Cuprate super.
Organic super.
Pnictide super.
Host metal
Broken symmetry
insulator
Strange
metal
Broken symmetry
M. R. Norman, Science (2011)
superconductor
2000
Symmetry + correlation
Quantum
phase
transition
New direction
Time-reversal, particle-hole, chiral (sublattice) symmetry
From Fabian Hassler
2010
Generalized symmetry defines topology
Grand new challenge, new approach
From Leon Balents
Correlation
unknown
strong spin orbit
coupling
Layered, organic,
or oxide substrates
Symmetry + correlation + topology
Spin-orbit coupling
(topology)
2020
II.
Key Ideas
Research goal
New functionality
and devices
New low D physics
symmetry + topology
Key idea 2
Advanced
probe microscopy
Advanced
Photoelectron spectroscopy
Transport
New hybrid low D materials
Atomic layer + layered crystal + organic crystal
Key idea 1
Atomically controlled growth /interface
Atomic layer and wire self-assembled
Luttinger liquid
Broken symmetry
atomic rods
atomic wires
Yeom group, PRL (2008); (2009)
Atomic wire toward topology
Soliton
Yeom group, PRL (2012)
Giant Rashba effect
Yeom group, PRL (2013)
Atomic layer + wire + others
Metals with large
spin-orbit coupling
Bi2Te3
Bi monolayer
Pb
Semiconductors
Graphene
TI
Layered materials
Organic crystals
Oxides
Yeom group, submitted to PRL (2013)
Proximity coupling of different interactions
Key idea 1 - Atomic layer hetero-interface for new physics
strong spin orbit
coupling
graphene
Sb2Te3
Jhi group, PRB (2013)
Bi2Te3
NbSe2
Xue group, Science (2012)
Proximity coupling of different interactions
Layered, organic,
or oxide
Key idea 2 – New materials + Advanced probes
Spin/angle resolved
photoemission
Ultra low temperature
STM/AFM
Spin-resolved STM/AFM
Atomically
controlled growth
Spin resolved photoemission – world best !
High flux undulator
at Pohang Light Source
EPU
High flux laser
High-efficiency (x20)
spin detector
(Okuda, 2010)
Spin-polarized STM/AFM – unique machine !
< 10 mK
> 10 Tesla vector magnet
Superconducting
Conducting
(< 500 mK)
Magnetic
Tunneling
and force
III. Executive Plans
Organization
Scientific organization
Advanced probes
Atomically controlled growth
Atomic Layer Epitaxy
Microscopy
Chemical vapor
epitaxy
Local spectroscopy
Global spectroscopy
Theory/Simulation
Organic crystals /
films
Other correlated
materials
Transport
Devices
Scientific organization
Director
Advanced probes
Atomically controlled growth
Physics faculty
Microscopy
Local
spectroscopy
Global
spectroscopy
Materials
Group leader
Transport
Theory/Simulation
Layered
crystals
Chemistry
(or Materials)
Group leader
Organic
crystal
(or oxide film)
Devices
Best scientists through international competition
Group leaders
Layered material growth and device physics
Prof. Moon-Ho Jo
Yonsei University (Materials Science and Engineering)
1. Nano Lett. 12, 5913 (2012).
2. Nano Lett. 12, 855 (2012).
3. Adv. Mater. 24, OP49 (2011).
Organic-inorganic nanostructures
Prof. Hee Cheul Choi
POSTECH (Chemistry)
1. Angewante Chemie IE 51, 6383 (2012).
2. NPG Asia Mater. 4, e12 (2012).
3. Angewante Chemie IE 49, 9670 (2011).
Faculty
STM; Spin-polarized and multi-tip STM
Prof. Tae-Hwan Kim
POSTECH (Physics)


Scanning Tunneling Microscopy/Spectroscopy
Nanotransport
SNU – Oak Ridge National Lab.
STM; single molecule / single spin
Dr. Ung Don Ham
IBS
■
■
■
LT STM instrumentation
Scanning Tunneling Microscopy/Spectroscopy
Single molecule and single spin detection/manipulation
UC Irvine – SNU
Faculty
Atomic and Magnetic Force Microscopy
Prof. Jee Hoon Kim
POSTECH (Physics)


Atomic and Magnetic Force Microscopy
Superconductivity/heavy-Fermion materials
U. Texas – Harvard – Los Alamos National Lab.
Layered material synthesis and transport
Prof. Jun Sung Kim
POSTECH (Physics)
■
■
Synthesis and Single Crystal Growth
Electrical/Thermal Transport Under Extreme Conditions
SNU – Max Plank Stuttgard - POSTECH
Faculty
Angle-Resolved Photoelectron Spectroscpy
Prof. Keun Su Kim
POSTECH (Physics)


ARPES
Atomic monolayers and graphene
Yonsei U. – Lawrence Berkeley National Lab.
Electronic Structure Calculations
Dr. Sung Hoon Lee
IBS
■
■
DFT calculations
Surfaces, semiconductors, 2D crystals
POSTECH – Fritz Harber Institute - Samsung
Comparison and Identity
Advanced growth – hybrid interfaces
Princeton
(Cava) bulk materials
Tsinghua University
(Xue) MBE growth
MPI Stuttgart
(Kern) molecule
NIMS
(Aono) device
Synchrotron radiation
+
STM
Expt. (institute)
+
Theory (department)
Physics
+
Chemistry
+
Materials Science
Facility
Location
IBS POSTCH campus
To be constructed in 3 years
SPM
lab
By 2015
Uniqueness of POSTECH IBS campus
POSTECH Campus
Physics
Bldg
IBS
Bldg
PAL
NCNT
APTCP
Chemistry
Bldg
Current instruments and upgrade
Atomic layer epitaxy
ARPES
(>20 K)
+
Spin detector / Laser
+
3 T magnet
VT-STM
(>40 K)
LT-STM
(>6 K)
ULT-STM
(>0.5 K)
Large and competitive facility
World best spin-ARPES
Unique STM/AFM
(10 mK, 10 T, spin, ex-force)
Davis group Cornell
P. Balzer, MBS
No other place in the world
Material science infrastructure
Growth
Fabrication
Characterization
Collaboration
On site collaboration
IBS
Bldg
POSTECH Campus
Physics
Bldg
PAL
NCNT
APTCP
Chemistry
Bldg
On-site
partners
Strong Theory
group
Band calculations
Theory
MH Kang (Physics)
HW Lee (Physics)
BI Min
KS Kim
SH Jhi
Takimoto (APCTP)
JH Shim (Chemistry)
Center for Topological Matter (SRC)
Center for Complex Materials (CRi)
Max-Plank POSTECH Center
Asia Pacific Center for Theoretical Physics
Physics/Chemistry/Materials Engineering
International collaboration
Synchrotron
Radiation
Advance Light Source
(Nano ARPES)
HiSOR, Japan
(Spin detector)
UVSOR, Japan
(Dedicated beamline)
Spring-8
Research
IBM Almaden
A. Heinrich
Columbia
P. Kim
Cornell-Kavli
JW Park
Harvard-Kavli
HG Park
Tsinghua
QK Xue
RIKEN
K. Maki
U. Tokyo
S. Hasegawa
Fritz Haber Inst.
M. Wolf
U. Zurich
J. Osterwalder
Budget
Budget plan
Phase I 6.0 Billion Won /year
Outside
collaboration,
5%
Physics group 3.0 BWon /year
Others,
10 %
Materials group leader I 1.5 BWon /year
Lab construction
and maintenance,
10 %
Chemistry group leader II 1.5 BWon /year
Salary,
25 %
Materials,
25 %
Instruments,
25 %
Future expansion
Free electron laser
To be constructed in 4 years
Moving toward dynamics
Why IBS ?
Infrastructure
Large facility; SR beamline & STM
Interdisciplinary collaboration
Collecting high quality man power
Advanced SPM
SR Beamline
Contents
IV.
Yeom group current projects
Atomic layer + wire
Semiconductor
Proximity coupling of different interactions
Atomic wire 1D metal
Topological soliton
Luttinger liquid behavior
Spin-orbit (Rashba) interaction
Atomic wires on silicon surfaces
1 ~ 3 nm
Au/Si(553) or Au/Si(557)
In/Si(111) or Au/Si(111)
Indium wires on Si(111); CDW transition
> 130 K
< 120 K
Yeom et al., PRL (1999)
Yeom group, PRL (2005)
Yeom group, PRL (2004)
Soliton on CDW wire
Kim and Yeom, PRL (2012)
Constructing theory for Z4 topology solitons,
soliton manipulations
Molecular phase shifter on CDW wire
Pentacene on In atomic wires
From soliton (1D) to domain walls (2D)
Correlated layered material
IrTe2 Charge order vs super
1T-TaS – Mott vs CDW vs super
CuS
1T-TaS2 – Mott vs CDW vs super
Nat. Materials (2013)
-0.2
-0.6
120
100
80
60
40
20
-0.4
-0.2
0
0.2
0.4
0.6
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Domain walls in 2D CDW
To be subm. to Nature Comm.
Charge order with strong SO interaction
Charge ordering pattern on IrTe2
To be subm. to PRL
Atomic layer hetrointerface
Metals with large
spin-orbit coupling
TI
Layered materials
Organic crystals
Oxides
Proximity coupling of different interactions
Atomic layer 2D metal
2D Superconductivity
Giant Rashba system
Mott vs spin frustration
Disorder and liquid
Superconducting In atomic layer
Predicted by Eli and Yeom, PRL (2003)
Observed by Q. K. Xue’s group, Nature Phys. (2010)
In
Si
Kim and Yeom, unpublished
Super + TI (Rashba) heterointerface
(Majorana Fermion)
2D TI + super
Gaint Rashba + super
Pb superconductor on large SO interaction
Pb/IrTe2
Pb/Bi2Te2Se
Pb/BiTeI
Topological insulator heterointerface
Bi, Atomic layer 2D TI
2D/ 3D TI heterointerface
Atomic layer 2D TI
Submitted
Bi (strong SO) + 3D TI heterostructure
Submitted
Atomic layer + wire + other 2D electrons
Metals with large
spin-orbit coupling
Semiconductor
Correlated
Layered materials
Proximity coupling of different interactions
What can be done from now on
spin-orbit interaction
Semiconductors
Graphene
3D TI
Layered materials
Organic crystals
Oxides
electron correlation
Bottom-up solid state physics, atomically and directly accessed
Closing remarks – aim something large !
Large size group - collaboration
Large size facility
More importantly big idea…..big dream
Closing remarks
Original approach to low dim. materials
Unexplored and challenging physics
Strong idea + facility + collaboration