Universidad del País Vasco, San Sebastián A. Mugarza A. Närmann J. E. Ortega A. Rubio University...
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Transcript of Universidad del País Vasco, San Sebastián A. Mugarza A. Närmann J. E. Ortega A. Rubio University...
Universidad del País Vasco, San Sebastián
A. MugarzaA. NärmannJ. E. Ortega
A. Rubio
University of Wisconsin MadisonF. J. Himpsel
macroscopic “miscut” angle
Universidad Autónoma de MadridA. Mascaraque
E. G. Michel
University of OsnabrückS. Speller
A. Bachmann
0.6 0.4 0.2 0.00.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
3/d
[111] k
(Å
-1)
4/d 2/d
/d
k|| (Å-1)
L
º
0.6 0.4 0.2 0.00.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5[111]
2/d
/d
k
(Å
-1)
k|| (Å-1)
L
º
Terrace and step modulated surface wave functionprobed by photon-energy-dependent photoemissionJ. E. Ortega et al., Phys. Rev. Lett. 84, 6110 (2000)
Cu(111): pz-like surface state
Topographic scan
7º miscut Cu(111)
STM
Bottom of the surface band
Spectroscopic scan U= - 0,14V
Repulsive barrier at the step
Terrace width distribution
9º miscut
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0.5 1.0 (X)
0
5
80
100
120
kedge
k(E)
En
erg
y (e
V)
k (Å-1)
Envelope function (k(E))
Bloch oscillation (kedge)
Co
n=2, 3ML
n=3, 6ML
Cu
70 80 90 100 110 120 130-1
0
1
2
3
4
5
6
7
8
9
kedge k(E)k(E)
Cu/Co(100)
6 ML (n=3) 3 ML (n=2)
Pho
toem
issi
on I
nten
sity
Photon energy (eV)
-20 -15 -10 -5 0 5
-0.5
0.0
h
22 eV
terrace surface
Emission angle (deg)
-0.5
0.0
13 eV
Ene
rgy
rel.
to E
F
(eV
)
-0.5
0.0
-20 -15 -10 -5 5
9º miscut
10 eV
Dispersion on 100-like stepped Cu(111)
-20 -15 -10 -5 0 5
-0.5
0.0
h
22 eV
Emission angle (deg)
-0.5
0.0
13 eV
-0.5
0.0
-20 -15 -10 0 5 surface terrace
5º miscut
10 eV
[111]
L
d
d
E1
E2
E1
[111]
L
d
E2
2
L
k
k|| k||
kx 0.5
9º miscut 5º miscut
Accessible Photoemission Final
States
-25 -20 -15 -10 -5 0
-0.5
0.0
h
22 eV
Emission angle (deg)
-0.5
0.0
14 eV
Kin
etic
Ene
rgy
(eV
)
-0.5
0.0
-25 -20 -15 -10 -5 0
7º miscut
surface terrace
10 eV
Transition from terrace to step modulation
7º miscut (17 Å wide terraces)
-0.6 -0.4 -0.2 0.00.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5[111]
L
3/L
2 /L
/L
k (
Å-1)
k(Å-1)
6 8 10 12 14 16 18 20
-0,5
0,0
85 eV
Emission angle (deg)
-0,5
0,0
70 eV
Ener
gy re
l. to
Ef (
eV)
-0,5
0,0
60 eV
-0,5
0,0
6 8 10 12 14 16 18 20
20 eV
terrace
11 deg miscut, 111-like steps
Umklapp with step lattice vectors
L
-1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.00
1
2
3
4
5
6
d
[111]
k
(Å-1
)
k|| (Å-1)
d
d
L
º
EF
EF
Binding Energy (eV)
|| to the steps to the steps
1 0.51 0.5
Motion perpendicular to the step (scattering)
Motion parallel to the step (free motion)
5 deg miscut, (111)-like steps
-0,8 -0,6 -0,4 -0,2 0,0
h = 10 eV
x2
x2
x2
9º
7º
5º
miscut
111-like steps
Energy rel. to E F (eV)
Ph
oto
em
issi
on
In
ten
sity
-0,8 -0,6 -0,4 -0,2 0,0
h = 10 eV
5º
7º
9º
x2
miscut
100-like steps
One-dimensional state step state
1D State: sputtering test
clean
band bottom 15 deg off 19 deg off 22 deg off
band bottom 15 deg off 19 deg off 22 deg off
1 min sputtering || to the steps
band bottom 15 deg off 19 deg off 22 deg off
2 min sputtering to the steps
Clean 7 deg miscut,{111}-like steps
band bottom 15 deg off 19 deg off 22 deg off
LEED[10] spot
Dispersion to the
step: confinement Dispersion || to the
step: free motionFlat surface:
2D Image State
he-
14.5 eV
J. E. Ortega et al., Phys. Rev. B 49, 13859 (1994)
E
x y
Vacuum
(reference level)
2D Image State
1D Image State
(step state)
Charge smoothening at the step(Smoluchowsky dipole)
++++
----
eV
Vicinal Cu(100)[100]
[011]11 Å