Post on 29-Jan-2018
transcript
Vibrational Quantum TransportPhD defence June 4th, 2010Mads Engelund
Supervisors:Antti-Pekka JauhoMads Brandbyge
•Introduction•Basic approach•Results
DTU Nanotech, Technical University of Denmark2
DTU Nanotech, Technical University of Denmark
Moo
re, E
lect
roni
cs, 3
8, 3
(196
5)
3
DTU Nanotech, Technical University of Denmark
http
://co
mm
ons.
wik
imed
ia.o
rg/w
iki/U
ser:W
gsim
on
3
DTU Nanotech, Technical University of Denmark
Cou
rtesy
of R
ay K
urzw
eil
3
New transistor approaches
Song and Lee, Nature, 462, 1039 (2009)http://www.sciencedaily.com/releases/2009/12/091223133343.htm
DTU Nanotech, Technical University of Denmark4
Lin et al., Science, 327, 662 (2010)
New transistor approaches
Song and Lee, Nature, 462, 1039 (2009)http://www.sciencedaily.com/releases/2009/12/091223133343.htm
DTU Nanotech, Technical University of Denmark4
Lin et al., Science, 327, 662 (2010)
New transistor approaches
Song and Lee, Nature, 462, 1039 (2009)http://www.sciencedaily.com/releases/2009/12/091223133343.htm
DTU Nanotech, Technical University of Denmark4
Heat dissipation
DTU Nanotech, Technical University of Denmark7
Heat dissipationDoing work
Flickr.com/mikebaird
DTU Nanotech, Technical University of Denmark7
Heat dissipationDoing work
Flickr.com/mikebaird
Overheating
Flickr.com/mikebairdDTU Nanotech, Technical University of Denmark7
Ralph Group, Cornell University, http://people.ccmr.cornell.edu/~ralph/projects/emig_movies/
DTU Nanotech, Technical University of Denmark8
Ralph Group, Cornell University, http://people.ccmr.cornell.edu/~ralph/projects/emig_movies/
DTU Nanotech, Technical University of Denmark8
Heat
DTU Nanotech, Technical University of Denmark5
Heat
DTU Nanotech, Technical University of Denmark
=Energy we’ve lost track of
5
Heat
DTU Nanotech, Technical University of Denmark
=Energy we’ve lost track of
Public domain
5
DTU Nanotech, Technical University of Denmark
Vibrations =main storage of heat
Wikimedia commons
Macroscopic suspended beam
Microscopic graphene edge
6
Heat flow on different scales
DTU Nanotech, Technical University of Denmark9
Sierra Pacific Innovations: ww.x20.org
Heat flow on different scales
DTU Nanotech, Technical University of Denmark9
Sierra Pacific Innovations: ww.x20.org
IEEE Spectrum: Carbon Nanotubes Takes the Heat of Chips, Bryan Christie Design
Heat flow on different scales
DTU Nanotech, Technical University of Denmark9
Sierra Pacific Innovations: ww.x20.org
IEEE Spectrum: Carbon Nanotubes Takes the Heat of Chips, Bryan Christie Design
Wikimedia Commons
Heat flow on different scales
DTU Nanotech, Technical University of Denmark9
Sierra Pacific Innovations: ww.x20.org
IEEE Spectrum: Carbon Nanotubes Takes the Heat of Chips, Bryan Christie Design
Wikimedia Commons
Wikimedia Commons
Heat flow on different scales
DTU Nanotech, Technical University of Denmark9
ElectronicsPhotonicsVibronics?
10 DTU Nanotech, Technical University of Denmark
ElectronicsPhotonicsVibronics?
Physical Review Letters, 104, 083901(2010)
Saser
10 DTU Nanotech, Technical University of Denmark
ElectronicsPhotonicsVibronics?
Science, 314, 5802, 1121-1124(2009)
Thermal wave guide and rectifier
Physical Review Letters, 104, 083901(2010)
Saser
10 DTU Nanotech, Technical University of Denmark
DTU Nanotech, Technical University of Denmark
Measurements on vibrations
11
DTU Nanotech, Technical University of Denmark
Measurements on vibrations
Raman Spectroscopy
Nano Lett., 8-3, 919-924(2008)
11
DTU Nanotech, Technical University of Denmark
Measurements on vibrations
Raman Spectroscopy
Nano Lett., 8-3, 919-924(2008)
Thermal probing
J. of App. Phys., 105, 104306 (2009)
11
•Introduction•Basic approach•Results
DTU Nanotech, Technical University of Denmark12
Ab-initio• Data-> Basic principles -> model
EmpiricalData -> model
18 DTU Nanotech, Technical University of Denmark
Ab-initio• Data-> Basic principles -> model
EmpiricalData -> model
18 DTU Nanotech, Technical University of Denmark
Ab-initio• Data-> Basic principles -> model
EmpiricalData -> model
18
DFTAccurate tool but only app. 1000 atoms
DTU Nanotech, Technical University of Denmark
DTU Nanotech, Technical University of Denmark
Gold chains
13
DTU Nanotech, Technical University of Denmark
Gold chains
Eur. Phys. J. D, 16, 395(2001)
Simple structure
13
DTU Nanotech, Technical University of Denmark
Gold chains
Eur. Phys. J. D, 16, 395(2001)
Simple structure
13
Clear inelastic signal
Phys. Rev. Lett., 88, 216803(2002)
DTU Nanotech, Technical University of Denmark14
DTU Nanotech, Technical University of Denmark
The dynamical matrix
14
DTU Nanotech, Technical University of Denmark
The dynamical matrix
14
Equation of motion (Newton’s 2.)
DTU Nanotech, Technical University of Denmark
The dynamical matrix
14
Equation of motion (Newton’s 2.)
Green’s function
DTU Nanotech, Technical University of Denmark
DOS
Green’s function
DTU Nanotech, Technical University of Denmark
Leads
DOS
DTU Nanotech, Technical University of Denmark17
Calculating the Self-Energy
DTU Nanotech, Technical University of Denmark18
The Surface Green’s function
k
0
0
Discrete modes vs. broadened modes
Frequency/Energy
Den
sity
of S
tate
s
Discrete modes vs. broadened modes
Time
Am
plitu
de
Frequency/Energy
Den
sity
of S
tate
s
Discrete modes vs. broadened modes
Time
Am
plitu
de
Frequency/Energy
Den
sity
of S
tate
s
Discrete modes vs. broadened modes
Time
Am
plitu
de
Frequency/Energy
Den
sity
of S
tate
s
Discrete modes vs. broadened modes
DTU Nanotech, Technical University of Denmark
Q-factors
17
DTU Nanotech, Technical University of Denmark
Q-factors
17
DTU Nanotech, Technical University of Denmark
Q-factors
17
Am
plitu
de
0
Time
High Q-factor
Low Q-factor
Programming
DTU Nanotech, Technical University of Denmark19
8000 lines
getGreensFunction(system)
getSelfEnergy(system)getDynamicalMatrix(system)
getFCMatrix(system)
getFCMatrix(surface)
getlFCMatrix(crystal)
Read SIESTAResultRead
SIESTAResultRead
SIESTAResult
getSelfEnergy(surface)
getUnpertubedDynamicalMatrix(surface)
getSurfaceGreensFunctionPrDiffVector(surface)
getFCMatrix(surface)
getDynamicalMatrix(surface)
Programming
DTU Nanotech, Technical University of Denmark19
8000 lines
•Introduction•Basic approach•Results
–Gold Chains–Graphene edges
DTU Nanotech, Technical University of Denmark20
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
DTU Nanotech, Technical University of Denmark
Study of gold chains
21
Eur. Phys. J. D, 16, 395(2001)
24
24
Amplitude in chain
High
Hig
hLo
wQ
-fact
or
24
Amplitude in chain
High Low
Hig
hLo
wQ
-fact
or
24
Amplitude in chain
High Low
Hig
hLo
wQ
-fact
or
DTU Nanotech, Technical University of Denmark22
DTU Nanotech, Technical University of Denmark22
DTU Nanotech, Technical University of Denmark22
DTU Nanotech, Technical University of Denmark22
DTU Nanotech, Technical University of Denmark26
Length
DTU Nanotech, Technical University of Denmark27
Type of lead
DTU Nanotech, Technical University of Denmark
Gold Chains
DTU Nanotech, Technical University of Denmark
Gold Chains
•Instances of very low damping
DTU Nanotech, Technical University of Denmark
Gold Chains
•Instances of very low damping
Frederiksen et al., Phys. Rev. B, 75, 205413(2007)
DTU Nanotech, Technical University of Denmark
Gold Chains
•Instances of very low damping•Sensitivity
Frederiksen et al., Phys. Rev. B, 75, 205413(2007)
DTU Nanotech, Technical University of Denmark
Gold Chains
•Instances of very low damping•Sensitivity
quantrans.org/introduction
•Introduction•Basic approach•Results
–Gold Chains–Graphene edges
DTU Nanotech, Technical University of Denmark20
24 DTU Nanotech, Technical University of Denmark
www.als.lbl.gov/pics/154graphene01.png
24 DTU Nanotech, Technical University of Denmark
www.als.lbl.gov/pics/154graphene01.png
www.technologyreview.com/files/11636/graphene_x220.jpg
24 DTU Nanotech, Technical University of Denmark
www.als.lbl.gov/pics/154graphene01.png
www.technologyreview.com/files/11636/graphene_x220.jpg
Lin et al., Science, 327, 662 (2010)
24 DTU Nanotech, Technical University of Denmark
www.als.lbl.gov/pics/154graphene01.png
www.technologyreview.com/files/11636/graphene_x220.jpg
Lin et al., Science, 327, 662 (2010)
24 DTU Nanotech, Technical University of Denmark
IEEE Spectrum: Carbon Nanotubes Takes the Heat of Chips, Bryan Christie Design
DTU Nanotech, Technical University of Denmark
An interesting experiment
*Jia et al., Science, 2009, 323, 1701
25
DTU Nanotech, Technical University of Denmark
An interesting experiment
*Jia et al., Science, 2009, 323, 1701
elec
troni
c cu
rren
t
25
DTU Nanotech, Technical University of Denmark
An interesting experiment
*Jia et al., Science, 2009, 323, 1701
elec
troni
c cu
rren
t
25
DTU Nanotech, Technical University of Denmark
An interesting experiment
*Jia et al., Science, 2009, 323, 1701
elec
troni
c cu
rren
t
25
DTU Nanotech, Technical University of Denmark
An interesting experiment
*Jia et al., Science, 2009, 323, 1701
elec
troni
c cu
rren
t
25
DTU Nanotech, Technical University of Denmark
An interesting experiment
*Jia et al., Science, 2009, 323, 1701
elec
troni
c cu
rren
t
25
26 DTU Nanotech, Technical University of Denmark
26 DTU Nanotech, Technical University of Denmark
26 DTU Nanotech, Technical University of Denmark
02/28/2010Armchair edges in grapheneDTU Nanotech, Technical University of Denmark33
The quick description
DTU Nanotech, Technical University of Denmark27
Vibrations
DTU Nanotech, Technical University of Denmark27
Vibrations
Electrons
DTU Nanotech, Technical University of Denmark27
Vibrations
Electrons
DTU Nanotech, Technical University of Denmark27
Vibrations
Electrons
DTU Nanotech, Technical University of Denmark27
Vibrations
Electrons
?
e
e
e
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
e
Bia
s
Pot
entia
l ene
rgy
of e
lect
rons
<1.6
<1.6
02/28/2010Armchair edges in grapheneDTU Nanotech, Technical University of Denmark37
Graphene Edges
02/28/2010Armchair edges in grapheneDTU Nanotech, Technical University of Denmark37
Graphene Edges
*Jia et al., Science, 2009, 323,
02/28/2010Armchair edges in grapheneDTU Nanotech, Technical University of Denmark37
Graphene Edges
02/28/2010Armchair edges in grapheneDTU Nanotech, Technical University of Denmark37
Graphene Edges
02/28/2010Armchair edges in grapheneDTU Nanotech, Technical University of Denmark37
Graphene Edges
Bye, bye armchair dimer
Conclusions
30 DTU Nanotech, Technical University of Denmark
Phys. Rev. Lett., 88, 216803(2002)
Conclusions
• Vibrations sensitive to everything
30 DTU Nanotech, Technical University of Denmark
Phys. Rev. Lett., 88, 216803(2002)
Conclusions
• Vibrations sensitive to everything• Importance of ab-initio
30 DTU Nanotech, Technical University of Denmark
Conclusions
• Vibrations sensitive to everything• Importance of ab-initio• Control of matter
30 DTU Nanotech, Technical University of Denmark
Science, 2009, 323, 1701
Conclusions
• Vibrations sensitive to everything• Importance of ab-initio• Control of matter
30 DTU Nanotech, Technical University of Denmark
Science, 2009, 323, 1701
Phys. Rev. Lett., 104,
DTU Nanotech, Technical University of Denmark39
Background-Theoretical Modeling of Vibrational Properties
DTU Nanotech, Technical University of Denmark39
Background-Theoretical Modeling of Vibrational Properties
Non-conservative ForcesDundas et al., Nat. Nano., 4, 99-103(2009)
DTU Nanotech, Technical University of Denmark39
Background-Theoretical Modeling of Vibrational Properties
Non-conservative ForcesDundas et al., Nat. Nano., 4, 99-103(2009)
DynamicsMcEniry et al., Phys. Rev. B, 035446(2008)
DTU Nanotech, Technical University of Denmark39
Background-Theoretical Modeling of Vibrational Properties
Non-conservative ForcesDundas et al., Nat. Nano., 4, 99-103(2009)
Anharmonic TransportMingo,
Phys. Rev. B, 125402(2006)
DynamicsMcEniry et al., Phys. Rev. B, 035446(2008)
Vibrational Quantum TransportPhD defence June 4th, 2010Mads Engelund
Supervisors:Antti-Pekka JauhoMads Brandbyge