Effect of pressure and of oxygen content on superconductivity in the cuprate HgBa2CuO4+δ. A quantitative analysis based on indirect-exchange pairing
✍ Scribed by L. Jansen; R. Block
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 1023 KB
- Volume
- 230
- Category
- Article
- ISSN
- 0378-4371
No coin nor oath required. For personal study only.
✦ Synopsis
A quantitative analysis is presented of experimental pressure and oxygen-doping effects on the critical temperature of HgBa2CuO4+~ over a wide range of 3, covering both under-and overdoped compositions, on the basis of indirect-exchange pairing between conduction electrons via oxygen anions. The results clearly show that for 6 ~< 0.28, the oxygen doping process is not the same as cation doping in e.g. La2-~SrxCuO4: part of the doped oxygen fulfills a double role as hole dopant and as Cooper pair mediator. Furthermore, adding or extracting oxygen under experimental conditions is accompanied by a redistribution of oxygen anions in the unit cell, to or from the neighborhood of the CuO2 layer. This effect explains the surprisingly wide range of superconducting compositions (0.03 ~< 6 ~< 0.40) of the system. The observed, anomalous, upward shift in thermoelectric power for 6/> 0.28 is attributed to different sites of doped oxygen beyond that limit, affecting only hole conductivity.