Chemistry Reference
In-Depth Information
netization [
14
], DC transport [
12
], and superconducting gap measurements [
13
].
Macroscopic coherence is obtained from the first two methods (Fig.
4.24
), whereas
the gap measurements give the local character of the superconductivity (Fig.
4.25
).
Ozer et al. [
14
,
15
] employed the superconducting quantum interference device
(SQUID) to measure the superconductivity. This method eliminates the electrical
contact issues because the measurements are performed inductively. On the other
7
18
11
5
d (ML)
7
6
5
0.00
0.02
0.04
0.06
1/d
(
Å
1
)
Fig. 4.24
T
C
of Pb(111) films as a function of inverse film thickness.
Filled dots
show the magnetic
measurements [
14
];
open circles
correspond to transport measurements [
12
]
(a)
1.4
1.2
(b)
1.0
6.53K
6.24K
6.03K
6.400
0.8
6.355
0.6
5.72K
2 x stdev
6.300
5.29K
0.4
6.255
6.200
1.2
6.155
1.0
6.100
0.8
6.055
0.6
6.000
5.955
0.4
4
5
6
7
8
9
10
11
12
13
14
15
16
1.2
Thickness (ML)
1.0
0.8
0.6
0.4
-8
-6
-4
-2
0
2
4
6
8
Sample bias (mV)
Fig. 4.25
T
C
measurements from the opening of the superconducting gaps in scanning tunneling
spectroscopy. (
a
) Gap of 5, 6, and 7ML thick Pb films at various temperatures. (
b
)
T
C
s obtained
from the gap measurements in panel (
a
). Reproduced from [
13
]
