应用本征超导态理论计算铊系材料超导临界转变温度tc以及掺杂元素选择的研究.doc
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应用本征超导态理论计算铊系材料超导临界转变温度tc以及掺杂元素选择的研究,应用本征超导态理论计算铊系材料超导临界转变温度tc以及掺杂元素选择的研究页数：67字数：31202摘 要本文首先以邹壮辉等人提出的本征超导理论和等效价键分析方法为基础，计算了tl2ba2can-1cuno2n+4 (n=1-4)和tlba2can-1cuno2n+2.5 (n=1-5)共9种材料的超导临界温度tc，并对...
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应用本征超导态理论计算铊系材料超导临界转变温度Tc以及掺杂元素选择的研究
页数：67 字数：31202
摘 要
本文首先以邹壮辉等人提出的本征超导理论和等效价键分析方法为基础，计算了Tl2Ba2Can-1CunO2n+4 (n=1-4)和TlBa2Can-1CunO2n+2.5 (n=1-5)共9种材料的超导临界温度Tc，并对本征超导理论的Tc计算公式中的有效价电子通道数的取法作了优化处理。这9种超导材料Tc值的计算结果，除Tl2Ba2Ca3Cu4O12和TlBa2Ca4Cu5O12.5的误差偏大之外，其余7种超导体的计算Tc值和实验值基本相吻合。对于Tl2Ba2Can-1CunO2n+4晶体，n=3时，=0.6312，该系列晶体的Tc达到最大值；对于TlBa2Can-1CunO2n+2.5晶体，n=4时，=0.6313，该系列晶体的Tc达到最大值。
以金属原子的晶体结构为氧化物晶胞的基本框架，计算Tl2Ba2Can-1CunO2n+4晶体的间隙位置及间隙半径，分析铊系氧化物超导材料掺杂特点。计算结果表明：全部的氧原子都占据间隙半径较大的八面体间隙位置，计算值与实际相吻合；铜氧五面体的顶氧占据着晶格中最大的间隙位置，间隙球最有可能占据该位置，掺F的实验工作已经证实了这一规律[56-60]。另外，从尺寸因素和掺杂元素能否提供有效价电子两个因素出发，讨论掺杂后超导体Tc的变化，得出结论：F-, Ga+, In+, Tl+, Pb2+, Sn2+, Ge2+, C2+, Sb3+, As3+, Bi3+, N3+满足尺寸因素，可能进入Tl2Ba2Can-1CunO2n+4晶格中，占据间隙位置，并且能够提供有效价电子，有利于提高材料的Tc值。关键词：本征超导态理论，超导临界温度，TBCCO，间隙球，掺杂
Using the theory of intrinsic superconductive state to calculate the superconducting critical temperature of Tl-Ba-Ca-Cu-O superconductor and the study on the choice of doping elements Abstract
In this paper, firstly, based on the theory of itrinsic superconductive state and analyzing method of equivalent valence bond of Zou Zhuanghui, the critical temperatures of high superconductive materials Tl2Ba2Can-1CunO2n+4 (n=1-4) and TlBa2Can-1CunO2n+2.5 (n=1-5).are calculated, and the determination for the numbers of effective valence electron channel is optimized. For these 9 superconductors, the calculated values of critical temperature Tc are consistent with experimental values except for Tl2Ba2Ca3Cu4O12 and TlBa2Ca4Cu5O12.5 superconductors. For Tl2Ba2Can-1CunO2n+4 crystals, when is 0.6312, there is a highest value of Tc. For TlBa2Can-1CunO2n+2.5 crystals, when is 0.6313, there is a highest value of Tc.
It is assumed that the basic frame of oxide cell is just the crystal structure constituted by metal atoms in this paper, and then the interstitial positions and interstitial radii of Tl2Ba2Can-1CunO2n+4 superconductors are calculated, thus the doping characteristics of TBCCO superconductor is discussed. The calculated results show that all the oxygen atoms locate in the interstitial positions with a larger radius, which is in accordance with experimental measurement values. The apical oxygen of the CuO5 square-pyramids occupies the interstitial positions with the largest radius, thus the doping atoms are most likely to occupy this position, which has been demonstrated by experiments on high temperature superconducting materials with fluorine doped (ref. 56-60). Considering the size factor and the availability of effective valence electrons, we discuss the variation in the Tc of fluorine doped superconductors. Finally, it is concluded that F-, Ga+, In+, Tl+, Pb2+, Sn2+, Ge2+, C2+, Sb3+, As3+ ,Bi3+ and N3+ can occupy the interstitial positions of crystal lattice, and can provide effective valence electrons, which will be of benefit to improve the value of Tc.
Key Words: the theory of intrinsic superconductive state, critical superconductive temperature, TBCCO, interstitial radii, doped
目 录
任务书 i
中文摘要 ii
ABSTRACT iii
第1章 绪论 1
1.1 超导体的性质 1
1.1.1 超导电性的发现 1
1.1.2 零电阻性 1
1.1.3 临界磁场和临界电流 1
1.1.4 迈斯纳效应 2
1.1.5 约瑟夫森效应 2
1.1.6 同位素效应 3
1.1.7 能隙效应 3
1.2 课题研究方向和主要内容 3
1.3 课题研究意义 4
第2章 超导研究的国内外进展 7
2.1 超导材料实验研究 7
2.2 实用化高温超导材料研究 10
2.2.1 薄膜 10
2.2.2 块材 11
2.2.3 带材 12
2.3 高温超导技术应用 14
2.4 超导理论研究 15
2.4.1 金兹堡一朗道理论 15
2.4.2 BCS理论 17
2.4.3 RVB理论 18
2.4.3 本征超导理论 19
第3章 铊系超导材料超导临界温度计算 23
3.1 本征超导态理论Tc计算公式 23
3.1.1 公式简化 23
3.1.2 有关参数取法 23
3.2 铊系超导材料的晶体结构 24
3.2.1 Tl2Ba2Can-1CunO2n+4超导体的晶体结构 25
3.2.2 TlBa2Can-1CunO2n+2.5超导体的晶体结构 27
3.3 Tl2Ba2Can-1CunO2n+4超导体超导临界温度的计算 29
3.3.1 有效价电子数Ne和摩尔体积Va 29
3.3.2 有效价电子通道数neff 32
3.3.3 Tl2Ba2Can-1CunO2n+4超导临界温度Tc的计算 37
3.4 TlBa2Can-1CunO2n+2.5超导体超导临界温度Tc的计算 38
3.5 对计算结果的讨论 42
3.5.1对的讨论 43
第4章 铊系超导体间隙球的计算 45
4.1 由金属原子所构成的晶体结构 45
4.2 BCC晶体中的间隙 45
4.3 Tl2Ba2Can-1CunO2n+4晶体结构间隙球的计算 47
4.4 对计算结果的讨论 53
4.4.1 关于Tl2Ba2Can-1CunO2n+4掺杂的讨论 53
第5章 结论 55
参考文献 57
致谢 63
页数：67 字数：31202
摘 要
本文首先以邹壮辉等人提出的本征超导理论和等效价键分析方法为基础，计算了Tl2Ba2Can-1CunO2n+4 (n=1-4)和TlBa2Can-1CunO2n+2.5 (n=1-5)共9种材料的超导临界温度Tc，并对本征超导理论的Tc计算公式中的有效价电子通道数的取法作了优化处理。这9种超导材料Tc值的计算结果，除Tl2Ba2Ca3Cu4O12和TlBa2Ca4Cu5O12.5的误差偏大之外，其余7种超导体的计算Tc值和实验值基本相吻合。对于Tl2Ba2Can-1CunO2n+4晶体，n=3时，=0.6312，该系列晶体的Tc达到最大值；对于TlBa2Can-1CunO2n+2.5晶体，n=4时，=0.6313，该系列晶体的Tc达到最大值。
以金属原子的晶体结构为氧化物晶胞的基本框架，计算Tl2Ba2Can-1CunO2n+4晶体的间隙位置及间隙半径，分析铊系氧化物超导材料掺杂特点。计算结果表明：全部的氧原子都占据间隙半径较大的八面体间隙位置，计算值与实际相吻合；铜氧五面体的顶氧占据着晶格中最大的间隙位置，间隙球最有可能占据该位置，掺F的实验工作已经证实了这一规律[56-60]。另外，从尺寸因素和掺杂元素能否提供有效价电子两个因素出发，讨论掺杂后超导体Tc的变化，得出结论：F-, Ga+, In+, Tl+, Pb2+, Sn2+, Ge2+, C2+, Sb3+, As3+, Bi3+, N3+满足尺寸因素，可能进入Tl2Ba2Can-1CunO2n+4晶格中，占据间隙位置，并且能够提供有效价电子，有利于提高材料的Tc值。关键词：本征超导态理论，超导临界温度，TBCCO，间隙球，掺杂
Using the theory of intrinsic superconductive state to calculate the superconducting critical temperature of Tl-Ba-Ca-Cu-O superconductor and the study on the choice of doping elements Abstract
In this paper, firstly, based on the theory of itrinsic superconductive state and analyzing method of equivalent valence bond of Zou Zhuanghui, the critical temperatures of high superconductive materials Tl2Ba2Can-1CunO2n+4 (n=1-4) and TlBa2Can-1CunO2n+2.5 (n=1-5).are calculated, and the determination for the numbers of effective valence electron channel is optimized. For these 9 superconductors, the calculated values of critical temperature Tc are consistent with experimental values except for Tl2Ba2Ca3Cu4O12 and TlBa2Ca4Cu5O12.5 superconductors. For Tl2Ba2Can-1CunO2n+4 crystals, when is 0.6312, there is a highest value of Tc. For TlBa2Can-1CunO2n+2.5 crystals, when is 0.6313, there is a highest value of Tc.
It is assumed that the basic frame of oxide cell is just the crystal structure constituted by metal atoms in this paper, and then the interstitial positions and interstitial radii of Tl2Ba2Can-1CunO2n+4 superconductors are calculated, thus the doping characteristics of TBCCO superconductor is discussed. The calculated results show that all the oxygen atoms locate in the interstitial positions with a larger radius, which is in accordance with experimental measurement values. The apical oxygen of the CuO5 square-pyramids occupies the interstitial positions with the largest radius, thus the doping atoms are most likely to occupy this position, which has been demonstrated by experiments on high temperature superconducting materials with fluorine doped (ref. 56-60). Considering the size factor and the availability of effective valence electrons, we discuss the variation in the Tc of fluorine doped superconductors. Finally, it is concluded that F-, Ga+, In+, Tl+, Pb2+, Sn2+, Ge2+, C2+, Sb3+, As3+ ,Bi3+ and N3+ can occupy the interstitial positions of crystal lattice, and can provide effective valence electrons, which will be of benefit to improve the value of Tc.
Key Words: the theory of intrinsic superconductive state, critical superconductive temperature, TBCCO, interstitial radii, doped
目 录
任务书 i
中文摘要 ii
ABSTRACT iii
第1章 绪论 1
1.1 超导体的性质 1
1.1.1 超导电性的发现 1
1.1.2 零电阻性 1
1.1.3 临界磁场和临界电流 1
1.1.4 迈斯纳效应 2
1.1.5 约瑟夫森效应 2
1.1.6 同位素效应 3
1.1.7 能隙效应 3
1.2 课题研究方向和主要内容 3
1.3 课题研究意义 4
第2章 超导研究的国内外进展 7
2.1 超导材料实验研究 7
2.2 实用化高温超导材料研究 10
2.2.1 薄膜 10
2.2.2 块材 11
2.2.3 带材 12
2.3 高温超导技术应用 14
2.4 超导理论研究 15
2.4.1 金兹堡一朗道理论 15
2.4.2 BCS理论 17
2.4.3 RVB理论 18
2.4.3 本征超导理论 19
第3章 铊系超导材料超导临界温度计算 23
3.1 本征超导态理论Tc计算公式 23
3.1.1 公式简化 23
3.1.2 有关参数取法 23
3.2 铊系超导材料的晶体结构 24
3.2.1 Tl2Ba2Can-1CunO2n+4超导体的晶体结构 25
3.2.2 TlBa2Can-1CunO2n+2.5超导体的晶体结构 27
3.3 Tl2Ba2Can-1CunO2n+4超导体超导临界温度的计算 29
3.3.1 有效价电子数Ne和摩尔体积Va 29
3.3.2 有效价电子通道数neff 32
3.3.3 Tl2Ba2Can-1CunO2n+4超导临界温度Tc的计算 37
3.4 TlBa2Can-1CunO2n+2.5超导体超导临界温度Tc的计算 38
3.5 对计算结果的讨论 42
3.5.1对的讨论 43
第4章 铊系超导体间隙球的计算 45
4.1 由金属原子所构成的晶体结构 45
4.2 BCC晶体中的间隙 45
4.3 Tl2Ba2Can-1CunO2n+4晶体结构间隙球的计算 47
4.4 对计算结果的讨论 53
4.4.1 关于Tl2Ba2Can-1CunO2n+4掺杂的讨论 53
第5章 结论 55
参考文献 57
致谢 63
