Superconductivity in CaCuO2 as a result of field-effect doping.
Understanding the doping mechanisms in the simplest superconducting copper oxide-the infinite-layer compound ACuO2 (where A is an alkaline earth metal)-is an excellent way of investigating the pairing mechanism in high-transition-temperature (high-Tc) superconductors more generally. Gate-induced modulation of the carrier concentration to obtain superconductivity is a powerful means of achieving such understanding: it minimizes the effects of potential scattering by impurities, and of structural modifications arising from chemical dopants. Here we report the transport properties of thin films of the infinite-layer compound CaCuO2 using field-effect doping. At high hole- and electron-doping levels, superconductivity is induced in the nominally insulating material. Maximum values of Tc of 89 K and 34 K are observed respectively for hole- and electron-type doping of around 0.15 charge carriers per CuO2. We can explore the whole doping diagram of the CuO2 plane while changing only a single electric parameter, the gate voltage.
Schön
J H
JH
Bell Laboratories, Lucent Technologies, 600 Mountain Avenue, Murray Hill, New Jersey 07974-0636, USA. hendrik@lucent.com
Dorget
M
M
Beuran
F C
FC
Zu
X Z
XZ
Arushanov
E
E
Deville Cavellin
C
C
Laguës
M
M