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Laboratoire National des Champs Magnétiques Intenses
Toulouse
Fermi Surface part II: measurements
Cyril PROUST
Periodic Table of the Fermi Surfaces of Elemental S olids
http://www.phys.ufl.edu/fermisurface/
Outline
I. Why and how to measure a Fermi surface ?
II. Angular Resolved Photoemission Electron Spectroscopy (ARPES)
III. Quantum oscillations (QO)1) History2) Theory
a) Semiclassical theorya) Landau levels quantificationb) Lifshitz-Kosevich theoryc) High magnetic field phenomena
3) High magnetic fields facilities4) Fermiology
IV. Hot topics1) Phase transition2) High Tc superconductors
I. Why and how to measure a Fermi surface
1D
2D
3D
EF ~ 1-10 eV
Typical excitations (∆V, ∆T) ~meV
( ))cos()cos(2)( bkaktkE yx +−=r
FS measurements
Global properties: Cv, χPauli, RH, ∆ρ/ρ...
Topographic properties: ARPES, AMRO, QO
2D:
Comparison with band structure calculations, effect of interactions, phase transitions…
Outline
I. Why and how to measure a Fermi surface ?
II. Angular Resolved Photoemission Electron Spectroscopy (ARPES)
III. Quantum oscillations (QO)1) History2) Theory
a) Semiclassical theorya) Landau levels quantificationb) Lifshitz-Kosevich theoryc) High magnetic field phenomena
3) High magnetic fields facilities4) Fermiology
IV. Hot topics1) Phase transition2) High Tc superconductors
II. ARPES Photoelectric effect:
1886: 1st experimenal work by Hertz
1905: Theory by Einstein
φυ −−= Bkin EhE
Work function of thesurface (Potential barrier)
Binding energy of theelectron in the solid
II. ARPES
X. J. Zhou et al, Treatise of HTSC
Angular Resolved PhotoEmission Spectroscopy
Vacuum Conservation laws Solid
Ekin
K
EB
kν
φυ
hif
Bkin
kkk
EhErrr
=−
−−=
Angular ↔ Momentum resolved
II. ARPES
Synchroton SOLEIL
http://www.synchrotron-soleil.fr/
From IR to RX
II. ARPES
http://arpes.phys.tohoku.ac.jp/contents/calendar-e. html
II. ARPES
A. Damascelli, http://www.physics.ubc.ca/~quantmat/ARPES/PRESENTATIONS/Talks/ARPES_Intro.pdf
II. ARPES Conservation laws
Energy of the photoelectron outside the solid
m
KEkin
2
22h=
One match the free-electron parabolas inside and outside the solid to obtain k inside the solid
φυ −−= Bkin EhE
Φvaccum
Bottom valence band (E0)EB
Efinal
EB, E0 and Efinal are referenced to EF
Ekin is referenced to Evaccum
II. ARPES Conservation laws
νhif kkkrrr
=− Ultraviolet (hν < 100 eV) ⇒ khν=2π/λ=0.05 Å-1
2π/a=1.5 Å-1 (a=4 Å)
0=− if kkrr
or
Gkk if
rrr=−
Umklapp ⇒ Shadow bands or superstructures
1) The surface does not perturb the translational symmetry in the x-y plane:
//kr
is conserved (within )//Gr
θsin21
//// kinmEKkh
==
A. Damascelli et al, RMP’03
2) Abrupt potential change along z ⇒ is not conserved across the surface⊥kr
II. ARPES Conservation laws
But determination of needed for 3D system to map E(k)⊥kr
Hyp: Nearly free electron description for the final bulk Bloch states
( )0
22//
2
0
22
22)( E
m
kkE
m
kkE f −+=−= ⊥
rrh
rhr
φ+= kinf EE θ22//
2
sin2
kinEm
k =r
hand
( )02cos2
1VEmk kin +=⊥ θ
h
φ+= 00 EV
A. Damascelli et al, RMP’03
II. ARPES 2D case
If 0≈⊥iv ⇒
When k// is completely determined (2D), ARPES lineshape can be directly interpreted as lifetime
Γi, Γf → inverse lifetime of photoelectron and photoholevi, vf → group velocities ( )⊥⊥ ∂∂= kEv ii /h
A. Damascelli et al, RMP’03
II. ARPES Non-interacting case
A. Damascelli et al, RMP’03
II. ARPES Interacting systems
A. Damascelli et al, RMP’03
II. ARPES Example: Quasi-2D overdoped cuprate
A. Ino et al, PRB’02
Outline
I. Why and how to measure a Fermi surface ?
II. Angular Resolved Photoemission Electron Spectroscopy (ARPES)
III. Quantum oscillations (QO)1) History2) Theory
a) Semiclassical theorya) Landau levels quantificationb) Lifshitz-Kosevich theoryc) High magnetic field phenomena
3) High magnetic fields facilities4) Fermiology
IV. Hot topics1) Phase transition2) High Tc superconductors
III.1 History1930 de Haas-van Alphen / Shubnikov-de Haas effects
W.J. de Haas
(1878-1960)
P.M. van Alphen
(1906-1967)
Bismuth
105 M/H
H
L.V. Shubnikov
(1901-1937)
David Shoenberg (1911 - 2004)
The experimental pioneer …
III.1 History
and his friend the other post-doc
L.D. Landau (1908 – 1968)
III.1 History
1950 – 70: Two decades of mapping 3D Fermi surfaces of ‘simple’ metals.
Periodic Table of the Fermi Surfaces of Elemental S olids
http://www.phys.ufl.edu/fermisurface/
III.2 TheorySemiclassical theory
Fdt
kd r
h
r1=
)(1
kv k
r
h
r ε∇=
( )elEBVqdt
kd rrrr
h +×=⇒
Real space Momentum space
ky
kx
E
E+δE
χr
χ&r
Br
dtdd ..2 χχ &=Α
χχ dEdE .∇=r
ρχ&rh
r=∇ Ewith
dEqB
d2
h
& =Α TdEqB
d .2
h=Α cT ωπ /2=⇒ with
dA
dEBqc .
22
h
πω =
c
cm
qB=ωzk
cdE
dAm
&
h
=π2
2
⇒
χχχχ and ρρρρ are the projection of k and r in the plane ⊥ to B
III.2 Theory
Onsager relation
hnrdp )(. γ+=∫rr
Aqkhprrr += ∫ ∫Α+×=∫ ⊥ ρρρρ rrrrrrr
dqdBqdp ...
∫ ∫∫+×−=∫ ⊥ dSnBqdBqdp ...rrrrrrr ρρρ
)( γφ += ne
hn
2
Φ=h
eB
BA nn
( )γπ += neB
Anh
2
Bohr-Sommerfeld condition:
Φ−=Φ+Φ−=∫ ⊥ qqqdp 2. ρrr
with
Onsager relation
γ=0.5 for free electrons
III.2 Theory
( )5.02 += neB
Anh
πOnsager relation ( ) ( )5.0222 +=+ neB
kk yxh
ππ
B=0
Density of states
)n(ε
c/ ωε h
Landau tubes
Oscillation when An=AF(kz) ( )5.02 += neB
AFh
π
( )Be
An F 1
25.0
πh=+ Oscillation periodic in 1/B with
e
AF F
π2
h=
⇔
⇔
III.2 Theory
• Free electrons in high magnetic fields ⇒ Landau levels (LL)
++=+= ⊥2
1
2
22
nm
kEEE c
zz ωhh
( )2
2
1Aqp
mH
r−= ⇒
3D
( ) )(2
1
2)(
22
02
222
xxxmm
px
m
kE c
xz ϕωϕ
−+=
− h
)0;;0( BxA =r
(jauge de Landau)
Equation of a harmonic oscillator with pulsation ωc and orbits centred atqB
kx
yh=0
Solutions:
• Degeneracy of each Landau level gL: xLx << 00h
xy
qBLk <<0
Quantum theory
y
xL
L
qBLg
π2/
h=
Bq
LLg yxLh
=
⇒
⇒
• Density of states (1 LL): n(Ez)=2*gL*n1D(Ezn)z
zzDE
mLEn
12)(
5.0
21
=h
where
For a given E ∑+−
=∞
=0
2/3
2 )5.0(
122)(
nc
cnE
mVEn
ωωπ
hh
h
kz
εF
cωh
E3D
B=0
Density of states
)n(ε
c/ ωε h
III.2 Theory
++=+= ⊥2
1
2
22
nm
kEEE c
zz ωhh
c
cm
qB=ω ∑+−
=∞
=0
2/3
2 )5.0(
122)(
nc
cnE
mVEn
ωωπ
hh
h
⇓Oscillation of most electronic properties
Magnetization: de Haas-van Alphen (dHvA)
Resistivity: Shubnikov-de Haas (SdH)
III.2 Theory
kz
εF
cωh
Temperature / Disorder effects on quantum oscillations
*cm
eBω =
kBT / τh=Γ
• Low T measurements
• Need high quality single crystals
τω hh >c
1>τωc
TkBc >ωh
⇒
−∝ γB
F2πsRR∆M∆R, DT inRS
Dingle temperature(mean free path)
Extremal area
Cyclotron mass
III.2 TheoryLifshitz-Kosevich theory (1956)
T≠≠≠≠0
p=1
Onsager relation ⇒ AF
⇒ m*
⇒
−=
×−=
×==
=
Bexp
694.14exp
/694.14 where)(
2
µπ
B
mTR
BTmXXsh
XR
B
A
πqB
F
cDD
cT
Fh
τπ B
Dk
T2
h=
= gmR *
bS2
cosπ
⇒ gmb
*
Direct measure of the Fermi surface extremal area (but number of orbits ? location in k-space ?)
B
B10 20 30 40 50 60
-3
-2
-1
0
∆R /
R
B (T)
(4)
(1) or (2)
(3)
(1)+(3)
Extremal Area
(4)
(1)
(3)
F=500 T
F=250 T
F=230 T
III.2 Theory
III.2 TheoryEnergy scales
For kF ≈ 7 nm-1 (large FS)
eB
kr F
c
h=
−=l
crπexp
)/sinh(
/
0
0
BTmu
BTmuR
c
cT =Dingle term
(the evil term!)
Temperature damping term
• kBT=0.09 meV/K ⇒ 1 meV=11.6 K • gµBB=0.12 x B meV / T
TmeVc [email protected]=ωh
TmeVBm
eBc /12.0 ×== hhω•
gµBB=4.6 meV @ 40 T
• cyclotron orbits
kF=7 nm-1 ⇒ rc=100 nm @ 40 T
kF=1.3 nm-1 ⇒ rc=14 nm @ 40 T
III.2 TheoryEffect of interactions
Electrons in Fermi gas at T=0 Electrons in Fermi liquid at T=0
Sus
c. (
arb.
uni
ts)
13
110 me
70 me60 me
50 me
70 me
Am
plitu
de (
arb.
uni
ts)
F (kilotesla)0 2 8 10
UPt3
L. Taillefer et al, J. Magn. Magn. Mater’87
III.3 High magnetic fields lab.
0.00 0.05 0.10 0.15 0.200
10
20
30
40
50
60
B (
T)
t (s)
Bmax
= 61 T
tmontée
= 25 ms
tdescente
= 110 ms
Decreasing:
~ 100 – 250 ms
Numerical lock-inHigh speed digitizer R
Piezoresistif cantilever
BMrr
×=τ
24 MW 300 l/s
DC field installation LNCMI Grenoble
III.3 High magnetic fields lab.
III.4 Fermiology
Alkali metals:
Li: 1s2s1
Na: [Ne]3s1
K: [Ar]4s1
Rb: [Kr]5s1
Cs: [Xe]6s1
1 conduction electron (body-centered cubic)
32
3 2
3 a
kn F ==
π
akF
π2620.0=
aN
π2707.0=Γ
⇒ The sphere is inside of the first Brillouin zone
Potassium
III.4 FermiologyPotassium
Aexp=(1.74 ±0.02) 1016 cm-2
Atheo=1.748 1016 cm-2 (free electron)
Deviation from the sphere
Fixed magnetic field and rotation
∆A ~ 10-4 A
e
AF F
π2
h=
III.4 FermiologyNoble Metals: Cu, Ag, Au (f.c.c.)
Li: 1s2s1 -Na: [Ne]3s1 -K: [Ar]4s1 Cu: [Ar]3d104s1
Rb: [Kr]5s1 Ag: [Kr]4d105s1
Cs: [Xe]6s1 Au: [Xe]4f145d106s1
d-bands
Free electron models:
FS=sphere inside the FBZ
III.4 Fermiology
<111>
A.S. Joseph et al, Phys. Rev’66
<100>
<110>
Dog’s bone Lemon
4-corner Rosetta6-corner Rosetta
III.4 FermiologyARPES in Cu
P. Aebi et al, Surface Science’94
III.4 Fermiology
3D 2D Q2D
Quasi 2D case
III.4 Fermiology
D. J. Singh, PRB’95
Band structure calculations
Sr2RuO4: a Quasi-2D Fermi liquid (school case…)
3 sheets of FSα hole like
β, γ electron like
III.4 FermiologySr2RuO4
A. P. Mackenzie et al, PRL’96
β
III.4 Fermiology
∆
−∝ )tan(cos
2γBcos
F2πsRR∆M∆R, 00DT θ
θπ
θckJ
B
FJinR FS
∆F
C. Bergemann et al, PRL’00
C. Bergemann et al, Advances in Physics’03
III.4 FermiologySr2RuO4
C. Bergemann et al, Advances in Physics’03
III.4 FermiologySr2RuO4: Angular dependence of the amplitude of QO
αααα ββββ
γγγγ
C. Bergemann et al, Advances in Physics’03
III.4 FermiologySr2RuO4
C. Bergemann et al, Advances in Physics’03
III.4 FermiologyARPES in Sr 2RuO4
First measurements give results different from band structure calculations!
III.4 FermiologyARPES in Sr 2RuO4
BUT surface atomic reconstruction seen by STM (Matzdorf et al. Science’00)
Solution: Sample cleaved at 180 K ⇒ surface-related features are suppressed !
Outline
I. Why and how to measure a Fermi surface ?
II. Angular Resolved Photoemission Electron Spectroscopy (ARPES)
III. Quantum oscillations (QO)1) History2) Theory
a) Semiclassical theorya) Landau levels quantificationb) Lifshitz-Kosevich theoryc) High magnetic field phenomena
3) High magnetic fields facilities4) Fermiology
IV. Hot topics1) Phase transition2) High Tc superconductors
IV. Hot topicsQO across the metagnetic transition in Sr 3Ru2O7
βδ γ1
α1α2
Paramagnet close to ferromagnetism (small moment)
J.F. Mercure et al, PRB10
IV. Hot topicsQO across the metagnetic transition in CeRh 2Si2 0 5 10 15 20 25 30
-4
-2
0
2
4
6
8
CeRh2Si
2
T = 50 mKB // [001]
Tor
que
(arb
. uni
ts)
µ0H (Tesla)
12 16 20 24 28 32
-5
0
5
... and above
Below the transition
Osc
illa
tory
tor
que
(arb
. uni
ts)
Field (Tesla)
0 5 10 15 200
2
4
6
8
Fabove
=16 kT
Fbelow
=1.8 kT
Am
plit
ude
(arb
. uni
ts)
dHvA frequency (kT)
10-25 T (below the transition) 27.5-32 T (x10, above)
W. Knafo et al, PRB10I. Sheikin et al, unpublished
IV. Hot topicsQO in high T c superconductors
PSEUDOGAP FERMIliquid
Platé et al, PRB’05
Tl2Ba2CuO6+δp~0.25
Hussey et al, Nature’03
Mott insulator
½ fillingstrong e-e repulsion
AF ground state
Photo credit: N. Hussey
Oscillation amplitude < 1% (1 m ΩΩΩΩ) !
B. Vignolle et al, Nature’08
kAF2
0
2πφ=
IV. Hot topicsOverdoped Tl 2Ba2CuO6+δδδδ
F=18100 ± 50 T
Hussey et al, Nature’03
AMRO
kF=7.35 ±±±± 0.1 nm -1
65 % of the FBZ
kAF2
0
2πφ=Onsager relation :
⇒ Carrier density: n=1.3 carrier /Cu atom (n=1+p with p=0.3)
02)2(
2
φπFA
n k ==Luttinger theorem :
⇒ kF=7.42 ± 0.05 nm-12Fk kA π=
2el mJ/mol.K27γ ±=For overdoped polycristalline Tl-2201: (Loram et al, Physica C’94)
*
2
22BA
el m3
akπNγ
h= ⇒
2el mJ/mol.K16γ ±=Electronic specific heat:
Effective mass : m*= (4.1 ± 1) m0BTmX
Xsh
XR cT /694.14
)( ×== ⇒
Mean free path : ldHvA≈320 Å (ltransp≈670 Å)
−=
l
h
Be
kR FT
πexp ⇒
IV. Hot topicsOverdoped Tl 2Ba2CuO6+δδδδ
PSEUDOGAP FERMIliquid
?underdoped
ARPES⇒ Fermi arcs
IV. Hot topics
IV. Hot topicsARPES in underdoped HTSC
Ca2-xNaxCuO2Cl2 K. Shen et al., Science’05
PSEUDOGAP
PSEUDOGAP FERMIliquid
?underdoped
ARPES⇒ Fermi arcs
IV. Hot topics
IV. Hot topics
underdopedYBa2Cu3Oy
Shubnikov - de Haas de Haas – van Alphen
Piezoresistif cantilever
D. Vignolles
C. Jaudet et al, PRL’08
N. Doiron-Leyraud et al, Nature’07
IV. Hot topics
1.7 1.8 1.9 2.0-4
0
4
Aim
anta
tion
(u.a
.)100 / B (T-1)kAF
20
2πφ=
underdopedYBa2Cu3O6.5
overdopedTl2Ba2CuO6+δδδδ
B
1.7 1.8 1.9 2.0
-2
0
2
∆R (
mΩ
)
100 / B (T-1)
B. Vignolle et al, Nature’08N. Doiron-Leyraud et al, Nature’07
IV. Hot topics
YBa2Cu3O6.5
Frequency : F = (530 ± 20) T
Ak = 5.1 nm-2
= 1.9 % of 1st Brillouin zone
Tl2Ba2CuO6+δδδδ
Frequency : F = (18100 ± 50) T
Ak = 173.0 nm-2
= 65 % of 1st Brillouin zone
n=1.3 carrier /Cun=0.038 carrier/Cu
0φF
n =
Radical change of the carrier density
Degeneracy lift
Example of Fermi surface reconstruction (commensurate case)
e.g. competing order- AF order (π, π)- d-density wave
IV. Hot topics
2 hole pockets
FSdH=990 T
nh=0.138 hole/Cu atom
1 electron pocket
ne=0.038 electron/Cu atom
FSdH=530 T
Fermi surface reconstruction (commensurate case)
e.g. competing order- AF order (π, π)- d-density wave
Higher mobility at low T
n=nh-ne=p=0.1
…
IV. Hot topics
underdoped overdoped
Topological change in FS:Broken symmetry
?
IV. Hot topics
ReferencesARPES:- A. Damascelli, Z-X Shen and Z. Hussain, " Angle-resolved photoemission spectroscopy of the cuprate superconductors", Rev. Mod. Phys. 75, 473 (2003)
- A. Damascelli, Z-X Shen and Z. Hussain, " Probing the Electronic Structure of Complex Systems by ARPES", Physica Scripta. 109, 61 (2004)
- S. Hüfner, ‘‘Photoelectron Spectroscopy,’’ (Springer-Verlag, Berlin, 1995)
- http://www.physics.ubc.ca/~quantmat/ARPES/PRESENTATIONS/talks.html
- http://www-bl7.lbl.gov/BL7/who/eli/SRSchoolER.pdf
Quantum oscillations:
- D. Shoenberg, "Magnetic oscillations in metals" (Ed. Cambridge Monographs on Physics)
- W. Mercouroff, "La surface de Fermi des métaux" (Ed. Masson)
- C. Bergemann, A. Mackenzie, S. Julian, D. Forsythe and E. Ohmichi, " Quasi-two-dimensional Fermi liquid properties of the unconventional superconductor Sr2RuO4", Advances in Physics 52, 639 (2003)
I. Why and how to measure a Fermi surface
TEgkT
UC FBv ×=
∂∂= )(
3
2π∫=FE
dEEfEnEU0
)()(
22
*
)(πh
FF
kmEg =
Global properties
• Specific heat where
• Pauli susceptibility )(2
2
FB
Pauli Eggµχ =
• Hall effectnqB
Rxy
H
1==ρ
• Magnetoresistance ∫==SF
24π
S.dkδvevneJ
rrrrr
Eeτ
kδr
h
r=
ES.dv4π
τeJ
SF3
2 rrr
h
r
∫=
wherekδr
AMRO
Work at 2D and for simple Fermi surface
Angular dependence of the MagnetoResistance Oscilla tions
At particular angles (‘Yamaji angles’)
01 =
∂∂=
z
zk
Ev
h
Semi-classical effectC. Bergemann et al, Advances in Physics’03
AMRO
• Two-axis rotation probe
Br
Θ → Polar angle
ϕ → Azimutal angle
• Steady magnetic fields
AMRO
Max. of the magnetoresistance when )4/1()tan(// ±=Θ ikc i π
Projection of kF in the plane ⊥ to B
0 20 40 60 80 100 120 140 160 180
ϕ =
R/R
Θ=9
0°, B
=15
T
Θ (°)
100
110
120
130
140
160150
170180
90
0 20 40 60 80 100 120 140 160 1802000
4000
6000
8000
R (
Ω)
Θ (°)
70 80 90 100 110
8000
8100
8200
8300
8400
R (
Ω)
Θ (°)
Quasi-2D organic metal:(BED0-TTF)2ReO4H2O
C. Proust et al, Synthetic Metals’99
AMRO
-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12
3
4
5
6
7
8
index
-tan (Θ)
Quasi-2D organic metal: (BED0-TTF)2ReO4H2O
0.0
0.1
0.2
0
20
40
60
80100
120
140
160
180
200
220
240
260 280
300
320
340
0.0
0.1
0.2
ϕ
k// (A-1)
)4/1()tan(// ±=Θ ikc i π
C. Proust et al, Synthetic Metals’99
III.2 Theory
Spin splitting: BgE Bµ=∆
Free electron: cm
eBB
m
eE ωhh
h ===∆002
*2
No change of the frequency but additional damping factor due to phase shift
=
∆= gmE
Rc
S 02
cos2cosπ
ωπh
Particular case: spin zero phenomena
Assume)cos(
)( 00 θ
θ mm =
0)cos(2
cos 0 =
=
θπ gm
RS
when ( )12
cos 0
+=
k
gmkθ
0 10 20 30 40 50 60 70 800
1
2
3
4
ampl
itude
(u.
a.)
Θ (°)
Spin splitting in Quantum oscillations
III.2 TheoryMagnetic breakdown (Cohen&Falicov 1961)
0 5 10 15 20 25 30 350
2
4
6
8
10
12
14
R /
RB
=0 -
1
B (T)
κ-(BEDT-TTF)2Cu(NCS)2
Probability p of MB
−=B
Bp 02 exp
F
c
Ee
mB
h
2
0
∆∝where
T=1.5 K
In strong magnetic fields, electron can tunnel from one orbit to another
∆ → ‘Energy gap’ (forbidden band) between the two orbits
III.2 TheoryLifshitz-Kosevich theory (1956)
TB
M
,µ
∂Ω∂−= ( )∑ −=Ω
electronsallFEEwhere Thermodynamic grand potentialT=0
∫ ∑
−++=Ω
=
0
0 0
22
2)5.0(
2
κω
πmn
nzFc
z dkEnm
kqBh
h
h
LL crosses EF
e
AF F
π2
h=
C. Bergemann, Thesis
III.3 High magnetic fields lab.
o LCMI (1992)
o LNCMP (1990)
o HLD (2006)o HFML (2003)
o continue
o pulsé
State of the art technical performances
Superconducting: USA: 33,8 T (NHMFL) (Commercial: 23 T Bruker)
Resistif : USA: 45,5 T (NHMFL, hybride)
Japan: 38,9 T (TML, hybride)
Europe: 35 T (LNCMI)
Pulsed : USA: 89,8 T (NHMFL)
Japan: 82 T (Osaka)
Europe: 87 T (HLD)
III.3 High magnetic fields lab.