Superconductivity modulated by quantum size effects.
We have fabricated ultrathin lead films on silicon substrates with atomic-scale control of the thickness over a macroscopic area. We observed oscillatory behavior of the superconducting transition temperature when the film thickness was increased by one atomic layer at a time. This oscillating behavior was shown to be a manifestation of the Fabry-Perot interference modes of electron de Broglie waves (quantum well states) in the films, which modulate the electron density of states near the Fermi level and the electron-phonon coupling, which are the two factors that control superconductivity transitions. This result suggests the possibility of modifying superconductivity and other physical properties of a thin film by exploiting well-controlled and thickness-dependent quantum size effects.
Guo
Yang
Y
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China.
Zhang
Yan-Feng
YF
Bao
Xin-Yu
XY
Han
Tie-Zhu
TZ
Tang
Zhe
Z
Zhang
Li-Xin
LX
Zhu
Wen-Guang
WG
Wang
E G
EG
Niu
Qian
Q
Qiu
Z Q
ZQ
Jia
Jin-Feng
JF
Zhao
Zhong-Xian
ZX
Xue
Qi-Kun
QK