| The discovery of high temperature superconductivity (HTSy), first in 1986 at 35 K in La{dollar}sb{lcub}2-x{rcub}{dollar}Ba{dollar}sb{lcub}x{rcub}{dollar}CuO{dollar}sb4{dollar} and later in 1987 at 93 K in {dollar}rm YBasb2Cusb3Osb{lcub}7-delta{rcub},{dollar} is considered one of the most exciting developments in physics in the final decades of this century. Tremendous efforts had been made to understand the mechanism of HTSy, which is still mysterious to us. One of the most important physical parameters which determines the superconducting transition temperature {dollar}(Tsb{lcub}c{rcub}){dollar} is the carrier density (n). The {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub}{dollar} system has drawn our special attention because it has the highest {dollar}Tsb{lcub}c{rcub}{dollar}'s at both ambient and high pressure discovered to date, a wide anion doping range, and a simple structure. Therefore, we have done a systematic doping study on {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub}{dollar} with {dollar}1leq mleq3,{dollar} by determining the O-diffusion process of {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub}{dollar} during annealing, the thermoelectric power (TEP) and {dollar}Tsb{lcub}c{rcub}{dollar}'s of samples with different O-dopings, and the pressure dependence of the {dollar}Tsb{lcub}c{rcub}{dollar}'s and the TEP's of samples with different O-dopings.; We found that: (1) The O-diffusion process for {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub}{dollar} is best described as bulk diffusion with an activation energy {dollar}sim{dollar}0.92 eV; (2) The room temperature thermopower S(290 K) of {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub}{dollar} roughly follows the canonical S(290 K)-vs-{dollar}Tsb{lcub}c{rcub}{dollar} correlation, while severe deviation exists in the heavily overdoped region, which might indicate the existence of another conduction band in {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub}{dollar} (3) The thermopower changes very little under pressure for the doping range examined for {dollar}rm HgBasb2CuOsb{lcub}4+delta{rcub}{dollar} and {dollar}rm H9Basb2Casb2Cusb3Osb{lcub}8+delta{rcub},{dollar} which is indicative of a very small charge transfer under pressure for {dollar}rm HgBasb2Casb{lcub}m-1{rcub}Cusb{lcub}m{rcub}Osb{lcub}2m+2+delta{rcub},{dollar} thus suggesting that there might be a new mechanism responsible for the large pressure effect on their {dollar}Tsb{lcub}c{rcub}{dollar}'s. |
