1
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Mark S. GoldenMark S. GoldenVan Van derder WaalsWaals--ZeemanZeeman InstituteInstitute
Universiteit van AmsterdamUniversiteit van AmsterdamFOMFOM--AA--1111
FermiologyFermiology of of bilayerbilayercolossal colossal magnetoresistantmagnetoresistant
manganitesmanganites
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
OutlineOutline
ARPES as kARPES as k--space microscopyspace microscopy
Summary, conclusions and outlookSummary, conclusions and outlook
Intro. to colossal magnetoIntro. to colossal magneto--resistant resistant maganitesmaganites
bilayerbilayer systems: Lasystems: La22--2x2xSrSr1+2x1+2xMnMn33OO77
AngleAngle--resolved photoemission data:resolved photoemission data:
status quostatus quoFermi surfacesFermi surfacesquasiparticlesquasiparticlescoupling to boson coupling to boson mode(smode(s))surprises in the temperature dependencesurprises in the temperature dependence
2
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
AmsterdamAmsterdam
Universiteit van AmsterdamUniversiteit van Amsterdam
375375 years oldyears old
2525 000 students, 2100 academic staff000 students, 2100 academic staff
'general' university 'general' university
Science FacultyScience Faculty
Van Van derder WaalsWaals--ZeemanZeeman Institute for Institute for Experimental PhysicsExperimental Physics
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
3
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Electronic, magnetic and optoelectronic Electronic, magnetic and optoelectronic properties of novel materialsproperties of novel materials
quantumquantumelectron matterelectron matter
optoelectronic optoelectronic materials materials ..
new magnetic new magnetic materials materials
and probesand probesCMPCMP
Condensed matter physics at the WZICondensed matter physics at the WZI
Anne de Anne de VisserVisser
JeroenJeroen GoedkoopGoedkoop
EkkesEkkes BrBrüückckTom Tom GregorkiewiczGregorkiewicz
Mark GoldenMark Golden
YingkaiYingkai HuangHuang
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Quantum Quantum mattersmatters
macroscopic 'laboratories' for quantum macroscopic 'laboratories' for quantum microscopicsmicroscopics
novel, multifunctional materialsnovel, multifunctional materials
unconventional quantum matter is undergoing a worldunconventional quantum matter is undergoing a world--wide boom:wide boom:
quantum phase transitionsquantum phase transitionsquantum criticalityquantum criticality
ambitious intellectual joint venture:ambitious intellectual joint venture:experiment & theoryexperiment & theory
electronelectronatomatom quantum matterquantum matter
4
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
What's emerging ?What's emerging ?
"at each new level of "at each new level of complexitycomplexity, , entirely new properties appear, and entirely new properties appear, and the understanding of these the understanding of these behavioursbehavioursrequires research which I think is as requires research which I think is as fundamental in its nature as any fundamental in its nature as any other."other."
P.W. Anderson, Science, 1972 P.W. Anderson, Science, 1972
simple building blockssimple building blocks
wellwell--known rules (QM)known rules (QM)
wholly wholly unexpectedunexpectedpropertiesproperties
VU
MIT
VU
MIT
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
'Axis of complexity' 'Axis of complexity' Piers ColemanPiers Coleman: Ann. Henri Poincaré 4 (2003) 1
not not ifif new phenomena will be discoverednew phenomena will be discovered
but but whenwhenwhere should one start looking first...?where should one start looking first...?
5
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Complexity Complexity →→ emergenceemergence
(almost by definition) experiment led(almost by definition) experiment led
creatingcreating unconventional quantum matter:unconventional quantum matter:
imagingimaging unconventional quantum matter:unconventional quantum matter:
in kin k-- or qor q--space (charge and/or spin)space (charge and/or spin)
in real spacein real space
in timein time understandingunderstanding
controlcontrol
no synthesis = no synthesis = no progressno progress
atoms + lasers: e.g. optical lattice matteratoms + lasers: e.g. optical lattice matter
atoms + chem. bonding: e.gatoms + chem. bonding: e.g. .
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
rr--space @ VTspace @ VT--STMSTMUHV, CreatecUHV, Createc
Advert:Advert: real space microscopy (STM / STS)real space microscopy (STM / STS)
Alex Groot, Freek Massee, Marco Gobbi
+ J.B. Goedkoop+ J.B. Goedkoop
HOPGHOPG
Si (7x7)Si (7x7)
(Pb,Bi)(Pb,Bi)--22122212BiBi--22122212
6
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
OutlineOutline
ARPES as kARPES as k--space microscopyspace microscopy
Summary, conclusions and outlookSummary, conclusions and outlook
Intro. to colossal magnetoIntro. to colossal magneto--resistant resistant maganitesmaganites
bilayerbilayer systems: Lasystems: La22--2x2xSrSr1+2x1+2xMnMn33OO77
AngleAngle--resolved photoemission data:resolved photoemission data:
status quostatus quoFermi surfacesFermi surfacesquasiparticlesquasiparticlescoupling to boson coupling to boson mode(smode(s))surprises in the temperature dependencesurprises in the temperature dependence
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Photoemission: a 'high' energy probePhotoemission: a 'high' energy probe
! High energy !! High energy !high energyhigh energy means 'sudden'means 'sudden'→→ simple to interpretsimple to interpret
photocurrent photocurrent vs.vs. EEkinkin and and angles angles θ,φθ,φ
7
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
)(),(,
2εε fkAiApfI
if∑ •∝
rr
matrix element Fermi function
ARPES : ARPES : physical quantity measuredphysical quantity measured
self energy: imaginary part
self energy: real part
spectral function
[ ] [ ]22 ),("),('),("1),(
εεεεε
πε
kkkkA
k Σ+Σ−−Σ=
hhννabsolute kabsolute k||||kk⊥⊥polarisationpolarisation
temperaturetemperature
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Our goal: the spectral functionOur goal: the spectral function
pic: after Meinders
nonnon--interacting systeminteracting system interactions oninteractions on
QPQP
8
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
ARPES:ARPES: shopping listshopping list
SLSSLS
pic: SPring8
Dam
asce
lli
UvA / PSIUvA / PSI
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Dam
asce
lliPhotoemission data: Photoemission data: structurestructure
||
EDMEDM
ReΣ
E-EF
Inte
nsity
EF
0
EDCEDC
MDCMDC
width in k2·ImΣ
9
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
OutlineOutline
ARPES as kARPES as k--space microscopyspace microscopy
Intro. to colossal magnetoIntro. to colossal magneto--resistant resistant maganitesmaganites
bilayerbilayer systems: Lasystems: La22--2x2xSrSr1+2x1+2xMnMn33OO77
Summary, conclusions and outlookSummary, conclusions and outlook
AngleAngle--resolved photoemission data:resolved photoemission data:
status quostatus quoFermi surfacesFermi surfacesquasiparticlesquasiparticlescoupling to boson coupling to boson mode(smode(s))surprises in the temperature dependencesurprises in the temperature dependence
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Potted history: colossal Potted history: colossal magnetoresistantmagnetoresistant manganitesmanganites
1969:1969:Searle & Wang, Can. J. Phys. 47, 2701 (1969)Searle & Wang, Can. J. Phys. 47, 2701 (1969)
LaLa11--xxPbPbxxMnOMnO33 -- giant (negative) giant (negative) magnetoresistancemagnetoresistancenear near TTCurieCurie
Essential theory:Essential theory:ZenerZener (1951), Anderson & Hasegawa (1955), de (1951), Anderson & Hasegawa (1955), de GennesGennes (1960)(1960)
double exchangedouble exchange
particular filling of the dparticular filling of the d--orbitals of the orbitals of the MnMn ionion++
10
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Ligand fieldsLigand fields
tt2g2g
ππ--bonding to bonding to ligandsligands
eegg
σσ--bonding to bonding to ligandsligands
picspics: : orbitronorbitron
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
MnMn valencyvalency: between 3 and 4: between 3 and 4
e.g. Lae.g. La0.670.67SrSr0.330.33MnOMnO33
0.67 x La0.67 x La3+3+
0.33 x Sr0.33 x Sr2+2+
3 x O3 x O22--
1 x Mn1 x Mn3.33+3.33+
0.670.67 1 1 11 1 1
3.67 Mn3d electrons3.67 Mn3d electrons
high spinhigh spin
11
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Double exchangeDouble exchange
ee ggel
ectro
n op
erat
or,
elec
tron
oper
ator
, ccii σσ
σσii localisedlocalised tt2g2g spin spin operators operators
JJHH onon--site FM site FM coupling between coupling between eegg spin and the tspin and the t2g2g
local spin (local spin (σσ))
t hopping of t hopping of eegg
electrons from one electrons from one MnMn site to nextsite to next
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Double exchangeDouble exchange
if if Hund'sHund's rule energy, J (rule energy, J (expexptt..: 2eV) > bandwidth, W: 2eV) > bandwidth, W
tteffeff = = t t coscos ((θ θ /2)/2)-- eegg spin always parallel to the tspin always parallel to the t2g2g spins and spins and -- θθ: angle between the t: angle between the t2g2g spins of the spins of the neighbouringneighbouring Mn'sMn's
12
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
RuddelsonRuddelson--Popper series (variations on Popper series (variations on perovskitesperovskites))
pic: Matt Rosseinsky
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Colossal (negative) Colossal (negative) magnetoresistancemagnetoresistance: CMR: CMR
double exchangedouble exchange means: means: ferromagnetic (FM) situation ferromagnetic (FM) situation favoursfavours hoppinghopping
in plane
out of plane
T. Kimura and Y. Tokura, Annu. Rev. Mat. Sci., 2000
quasi 2D structurequasi 2D structure→→ anisotropy in c and anisotropy in c and abab transport:transport:
CMR
CMR effects of 4000%CMR effects of 4000%
13
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
BilayerBilayer managanitesmanaganites
pic: Matt Rosseinsky
La,Sr,Orock salt
blocksdouble
MnO2planes
reduced dimensionalityreduced dimensionality
greater role for fluctuationsgreater role for fluctuationsconnection to theconnection to thehigh high TcTc cupratescuprates ??strong anisotropystrong anisotropy
(even) larger CMR effect(even) larger CMR effect
cleavagehere
cleavage surfaces suitablecleavage surfaces suitablefor surface sensitive probes:for surface sensitive probes:
ARPESARPESSTM / STSSTM / STS
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT,,xx phase phase diagrammediagramme
Hole doping, x
LaLa22--2x2xSrSr1+2x1+2xMnMn22OO77
LaLa22SrSr11MnMn22OO7 7 as 'parent insulator', as 'parent insulator', xx gives no. of additional holesgives no. of additional holes
why sowhy socomplex ?complex ?
Pic
ture
from
: Lin
g et
al.
PR
B 6
215
096
(200
0)
14
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Spins Spins ↔↔ charges charges ↔↔ orbitals (lattice)orbitals (lattice)
JahnJahn--Teller distortionsTeller distortions
select the select the eegg orbitalorbitaloccupancyoccupancy
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Spins Spins ↔↔ charges charges ↔↔ orbitals (lattice)orbitals (lattice)
orbital ordering orbital ordering
strain reduction strain reduction
magnetic order:magnetic order:within MnOwithin MnO22 plane, within plane, within bilayerbilayer, inter, inter--bilayerbilayer
charge orderingcharge ordering
MnMn3+3+ -- MnMn4+4+ -- MnMn3+3+ -- MnMn4+4+
15
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT,,xx phase phase diagrammediagramme
Hole doping, x
LaLa22--2x2xSrSr1+2x1+2xMnMn22OO77
Focus here:• FM metallic ground state
• CMR effect • max. Tc
Pic
ture
from
: Lin
g et
al.
PR
B 6
215
096
(200
0)
??
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Campbell, PRB2001
PolaronsPolarons, CO, OO above , CO, OO above TTcc
double exchange not sufficient for explaining PI phasedouble exchange not sufficient for explaining PI phase
polaronspolarons ((polaronicpolaronic correlations) above correlations) above TcTcOO and/or CO correlationsOO and/or CO correlationsstripeynessstripeyness
complex interplay of charge, spin, orbital degrees of complex interplay of charge, spin, orbital degrees of freedom still not understoodfreedom still not understood
16
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
OutlineOutline
ARPES as kARPES as k--space microscopyspace microscopy
Intro. to colossal magnetoIntro. to colossal magneto--resistant resistant maganitesmaganites
bilayerbilayer systems: Lasystems: La22--2x2xSrSr1+2x1+2xMnMn33OO77
Summary, conclusions and outlookSummary, conclusions and outlook
AngleAngle--resolved photoemission data:resolved photoemission data:
status quostatus quoFermi surfacesFermi surfacesquasiparticlesquasiparticlescoupling to boson coupling to boson mode(smode(s))surprises in the temperature dependencesurprises in the temperature dependence
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
OutlineOutline
ARPES as kARPES as k--space microscopyspace microscopy
Summary, conclusions and outlookSummary, conclusions and outlook
Intro. to colossal magnetoIntro. to colossal magneto--resistant resistant maganitesmaganites
bilayerbilayer systems: Lasystems: La22--2x2xSrSr1+2x1+2xMnMn33OO77
AngleAngle--resolved photoemission data:resolved photoemission data:
status quostatus quoFermi surfacesFermi surfacesquasiparticlesquasiparticlescoupling to boson coupling to boson mode(smode(s))surprises in the temperature dependencesurprises in the temperature dependence
17
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Expectations from band structure calculationsExpectations from band structure calculations
DFT says: DFT says: halfhalf--metallic metallic ferromagnetferromagnet2001
Pics from: Huang et al. PRB 62 13318 (2000)
X
M
Γ
Majority band: quasi-2D Fermi surface
3dx2-y2 BB
3dx2-y2 AB
3dz2-r2
eegg bandwidth: bothbandwidth: both3dx2-y2 and and 3dz2-r2 are occupiedare occupied
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
ARPES of 2L ARPES of 2L manganitesmanganites: : historyhistory
Colorado group:Colorado group:
ghost Fermi surface, pseudogapghost Fermi surface, pseudogapDessau Dessau et al.et al., PRL1998, PRL1998data: data: x=0.4x=0.4
Fermi surface nesting Fermi surface nesting (no(no QP'sQP's anywhere)anywhere)Chuang Chuang et al.et al., Science 2001, Science 2001datadata: : x=0.4x=0.4
hhνν=50eV=50eVintegrated integrated ±±200meV of E200meV of EFF
18
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
ARPES of 2L ARPES of 2L manganitesmanganites: : status quostatus quo
general statement 2L general statement 2L manganites: manganites: nodalnodal metalmetal(Fermi arc)(Fermi arc)data: data: x=0.4x=0.4
StanfordManella et al. Nature (2005)
ColoradoZ. Sun et al. PRL (2006)
QP'sQP's at at antinodeantinodeno no QP'sQP's forfor x=0.4x=0.4data: data: x=0.36x=0.36, 0.38, 0.4, 0.38, 0.4
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
ARPES of 2L ARPES of 2L manganitesmanganites: : status quostatus quo
ColoradoZ. Sun et al. Nature Physics (2007)
metallicity above metallicity above TTcc(phase separation)(phase separation)data: data: x=0.38, AB bandx=0.38, AB band
TTcc
19
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
aa
Enter Amsterdam. Enter Amsterdam. Crystal characterisation: x=0.36Crystal characterisation: x=0.36
sharp transitions, excellent cleavage surfacessharp transitions, excellent cleavage surfaces
FMFM--MM PMPM--II
TTcc = 130K= 130K
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Step 1: QP at Step 1: QP at antinode (antinode (ππ/a,0),/a,0), or not ?or not ?
S. de Jong et al. cond-mat/0611287Nov 2006 & W.K. Siu, MSc thesis 2006
20
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Step 2: Step 2: And betweenAnd between ((ππ/a,0) and/a,0) and BZ diagonal ?BZ diagonal ?
S. de Jong et al. 2006
FS map (EF± 15 meV)T= 30K, hv= 56eV. AB band only.
clear AB FS: clear AB FS: resembles LDA, resembles LDA, moderately nestedmoderately nested
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
X
Γ1234567
Hunting down the QP'sHunting down the QP's
low energy spectral weight alllow energy spectral weight all round the round the ABABFermiFermi surfacesurface
S. de Jong et al. 2006
hhνν=56eV=56eV
21
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
EnergyEnergy distribution distribution curvescurves
note:note:'QPs''QPs' at all at all kkFF's's for LSMOfor LSMO
S. de Jong et al. 2006
peaks not yet peaks not yet resolution resolution limited……limited……
hhνν=56eV=56eV
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
S. de Jong et al. 2006
antibonding band:antibonding band:sharp QP, resolution limited widthsharp QP, resolution limited width
µµ -- ARPES: AB band ARPES: AB band (at the SLS)(at the SLS)
hhνν=56eV=56eV
at (at (ππ/a,0)/a,0)
22
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
S. d
e Jo
nget
al.
2006
bonding band:bonding band:sharp QPsharp QP? extra feature? extra feature
bonding band:bonding band:EEFF MDC width (0.07 MDC width (0.07 ππ/a) is double that of the AB band/a) is double that of the AB band
hhνν=73eV=73eV
at (at (ππ/a,0)/a,0)
µµ -- ARPES: BB band ARPES: BB band (at the SLS)(at the SLS)
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
S. d
e Jo
nget
al.
2006
What about the BZ diagonal ?What about the BZ diagonal ?
FWHMFWHM0.07 0.07 ππ/a/a
FWHMFWHM0.1 0.1 ππ/a/a
23
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
kkFF EDC'sEDC's
S. d
e Jo
nget
al.
2006
for x=0.36: for x=0.36:
QP's visible for:QP's visible for:
AB FS at (AB FS at (ππ/a,0) /a,0) andand zone zone diagonal diagonal
and and for BB FS at (for BB FS at (ππ/a,0)/a,0)
((ππ/a,0)/a,0)
((ππ/a,0)/a,0)
BZ diagonalBZ diagonal
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
S. de Jong et al. 2006
coupling to collective (bosonic) mode(s):coupling to collective (bosonic) mode(s):clear deviation from nonclear deviation from non--interacting dispersion between 60 and 110meVinteracting dispersion between 60 and 110meValso seen in MDC width (also seen in MDC width (→→ QP inverse lifeQP inverse life--time)time)
Renormalisation effects at (Renormalisation effects at (ππ/a,0)/a,0)
T=30KT=30K
Width (π/a)0.200.150.10
-0.3
-0.2
-0.1
0.0
Position (π/a)0.200.10
-0.3
-0.2
-0.1
0.0
E-E
F(eV
)
24
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
OutlineOutline
Summary, conclusions and outlookSummary, conclusions and outlook
Intro. to colossal magnetoIntro. to colossal magneto--resistant resistant maganitesmaganites
bilayerbilayer systems: Lasystems: La22--2x2xSrSr1+2x1+2xMnMn33OO77
AngleAngle--resolved photoemission data:resolved photoemission data:
history, statushistory, status quoquoFermi surfacesFermi surfacesquasiparticlesquasiparticlescoupling to boson coupling to boson mode(smode(s))surprises in the temperature dependencesurprises in the temperature dependence
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Temperature dependence at (Temperature dependence at (ππ/a,0)/a,0)S
. de
Jong
et a
l.20
06
TTCC=130K=130K
25
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT--dependence: renormalisation effects (dependence: renormalisation effects (ππ/a,0)/a,0)
S. de Jong et al. 2006
peak position (kpeak position (kyy)) MDC FWHM (MDC FWHM (ππ/a)/a)(offset)(offset)
T=30T=30T=95T=95T=145T=145
hhνν=56eV=56eV
at (at (ππ/a,0)/a,0)
E-E
F(eV
)
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT--dependence:dependence:MDC width at (MDC width at (ππ/a,0)/a,0)
S. de Jong et al. 2006MDC FWHM (MDC FWHM (ππ/a)/a)
T=30T=30T=95T=95T=145T=145
hhνν=56eV=56eV
at (at (ππ/a,0)/a,0)strong Tstrong T--dependence for dependence for low energieslow energies
change in form change in form within FMwithin FM--M phase M phase (30 (30 →→ 95K)95K)
E-E
F(eV
)
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Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT--dependence: at (dependence: at (ππ/a,0) and BZ diagonal/a,0) and BZ diagonal
S. de Jong et al. 2006TTcc
hhνν=56eV=56eV
at (at (ππ/a,0)/a,0)
BZ diagonalBZ diagonal
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT--dependence: dependence: kkFF EDC's at (EDC's at (ππ/a,0) and BZ diagonal/a,0) and BZ diagonal
S. de Jong et al. 2006
giant temperature dependence. kgiant temperature dependence. k--dependent.dependent.QP peak more robust an antinodeQP peak more robust an antinodespectral weight shift even larger at nodespectral weight shift even larger at node
27
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
TT--dependence: metallic phase above dependence: metallic phase above TTcc ??
T30T30--T95T95
T95T95--T145T145
two phase model doesn't two phase model doesn't work herework here-- QP peak only for T<TcQP peak only for T<Tc-- different high E behaviour for the different high E behaviour for the two ktwo k--points points
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Some (founded) speculationsSome (founded) speculations
X
M
Γ
orbital fluctuations ?orbital fluctuations ?should be strong near 'FS approach' along diagonalshould be strong near 'FS approach' along diagonal
kk--dependence ofdependence ofTT--dep?dep?
relative supression of spectral relative supression of spectral weight at node ?weight at node ?
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Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Some (founded) speculationsSome (founded) speculations
phase separation (also above Tc) ?phase separation (also above Tc) ?Aarts, MydoshAarts, MydoshLSMO, 113LSMO, 113
RRøønnow nnow et al., LSMO 327, x=0.3et al., LSMO 327, x=0.3
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Some (founded) speculationsSome (founded) speculations
phase separation and photoemission data ?phase separation and photoemission data ?
Fermi step also well above Tc Fermi step also well above Tc
kk--dependence of spectra vs. dependence of spectra vs. temperature temperature
29
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
ConclusionsConclusions
no such thing as a (general) nodal metalno such thing as a (general) nodal metal
quasiparticles are to be found on both the AB (at quasiparticles are to be found on both the AB (at zone face zone face andand diagonal) and BB Fermi surfaces diagonal) and BB Fermi surfaces for x = 0.36for x = 0.36
strong renormalisation effects clearly identified:strong renormalisation effects clearly identified:-- phononphonon--orbitons orbitons -- strongly Tstrongly T--dep.: magnetism dep.: magnetism
anomalous temperature dependence:anomalous temperature dependence:-- huge shifts of spectral weighthuge shifts of spectral weight-- can't fit a 2can't fit a 2--phase modelphase model
analysis underwayanalysis underway
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Glimpse of something hot off the beamline......Glimpse of something hot off the beamline......
hhνν=56eV=56eV
S. de Jong et al. 2007
X
M
Γ
30
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
0 0.5 1.0 1.50 0.5 1.0 1.5
Glimpse 2Glimpse 2 hhνν=73eV=73eV
S. de Jong et al. 2007
X
M
Γ
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
? possible breakdown of 100% spin polarisation ?? possible breakdown of 100% spin polarisation ?
minority (LSDA) majority (LSDA)minority (LSDA) majority (LSDA)
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Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
0 0.5 1.0 1.50 0.5 1.0 1.5
Glimpse 2Glimpse 2 hhνν=73eV=73eV
S. de Jong et al. 2007
Phys.Kolloquium, TU Dresden. 26Phys.Kolloquium, TU Dresden. 26thth JuneJune,, 20072007©© Mark S. Golden 2007Mark S. Golden 2007
Quantum Electron Matter GroupQuantum Electron Matter Group, University of Amsterdam, University of AmsterdamSanne de Jong, Yingkai Huang, WingSanne de Jong, Yingkai Huang, Wing KiuKiu SiuSiu, , ImanIman SantosoSantoso, , WimWim KoopsKoops, , Freek Massee, Ton GortenmulderFreek Massee, Ton Gortenmulder
SLSSLSVladimir Vladimir StrocovStrocov, Luc , Luc PattheyPatthey, Ming Shi , Ming Shi
Support at BESSYSupport at BESSYRolf Follath, Patrick BresslerOlaf Schwarzkopf
FundingFundingFOM, EU, UvA
The CreditsThe Credits
Sanne de JongSanne de Jong
Yingkai HuangYingkai Huang