應(yīng)用本征超導(dǎo)態(tài)理論計算鉈系材料超導(dǎo)臨界轉(zhuǎn)變溫度tc以及摻雜元素選擇的研究.doc
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應(yīng)用本征超導(dǎo)態(tài)理論計算鉈系材料超導(dǎo)臨界轉(zhuǎn)變溫度tc以及摻雜元素選擇的研究,應(yīng)用本征超導(dǎo)態(tài)理論計算鉈系材料超導(dǎo)臨界轉(zhuǎn)變溫度tc以及摻雜元素選擇的研究頁數(shù)：67字?jǐn)?shù)：31202摘 要本文首先以鄒壯輝等人提出的本征超導(dǎo)理論和等效價鍵分析方法為基礎(chǔ)，計算了tl2ba2can-1cuno2n+4 (n=1-4)和tlba2can-1cuno2n+2.5 (n=1-5)共9種材料的超導(dǎo)臨界溫度tc，并對...
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應(yīng)用本征超導(dǎo)態(tài)理論計算鉈系材料超導(dǎo)臨界轉(zhuǎn)變溫度Tc以及摻雜元素選擇的研究
頁數(shù)：67 字?jǐn)?shù)：31202
摘 要
本文首先以鄒壯輝等人提出的本征超導(dǎo)理論和等效價鍵分析方法為基礎(chǔ)，計算了Tl2Ba2Can-1CunO2n+4 (n=1-4)和TlBa2Can-1CunO2n+2.5 (n=1-5)共9種材料的超導(dǎo)臨界溫度Tc，并對本征超導(dǎo)理論的Tc計算公式中的有效價電子通道數(shù)的取法作了優(yōu)化處理。這9種超導(dǎo)材料Tc值的計算結(jié)果，除Tl2Ba2Ca3Cu4O12和TlBa2Ca4Cu5O12.5的誤差偏大之外，其余7種超導(dǎo)體的計算Tc值和實驗值基本相吻合。對于Tl2Ba2Can-1CunO2n+4晶體，n=3時，=0.6312，該系列晶體的Tc達到最大值；對于TlBa2Can-1CunO2n+2.5晶體，n=4時，=0.6313，該系列晶體的Tc達到最大值。
以金屬原子的晶體結(jié)構(gòu)為氧化物晶胞的基本框架，計算Tl2Ba2Can-1CunO2n+4晶體的間隙位置及間隙半徑，分析鉈系氧化物超導(dǎo)材料摻雜特點。計算結(jié)果表明：全部的氧原子都占據(jù)間隙半徑較大的八面體間隙位置，計算值與實際相吻合；銅氧五面體的頂氧占據(jù)著晶格中最大的間隙位置，間隙球最有可能占據(jù)該位置，摻F的實驗工作已經(jīng)證實了這一規(guī)律[56-60]。另外，從尺寸因素和摻雜元素能否提供有效價電子兩個因素出發(fā)，討論摻雜后超導(dǎo)體Tc的變化，得出結(jié)論：F-, Ga+, In+, Tl+, Pb2+, Sn2+, Ge2+, C2+, Sb3+, As3+, Bi3+, N3+滿足尺寸因素，可能進入Tl2Ba2Can-1CunO2n+4晶格中，占據(jù)間隙位置，并且能夠提供有效價電子，有利于提高材料的Tc值。關(guān)鍵詞：本征超導(dǎo)態(tài)理論，超導(dǎo)臨界溫度，TBCCO，間隙球，摻雜
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 錄
任務(wù)書 i
中文摘要 ii
ABSTRACT iii
第1章 緒論 1
1.1 超導(dǎo)體的性質(zhì) 1
1.1.1 超導(dǎo)電性的發(fā)現(xiàn) 1
1.1.2 零電阻性 1
1.1.3 臨界磁場和臨界電流 1
1.1.4 邁斯納效應(yīng) 2
1.1.5 約瑟夫森效應(yīng) 2
1.1.6 同位素效應(yīng) 3
1.1.7 能隙效應(yīng) 3
1.2 課題研究方向和主要內(nèi)容 3
1.3 課題研究意義 4
第2章 超導(dǎo)研究的國內(nèi)外進展 7
2.1 超導(dǎo)材料實驗研究 7
2.2 實用化高溫超導(dǎo)材料研究 10
2.2.1 薄膜 10
2.2.2 塊材 11
2.2.3 帶材 12
2.3 高溫超導(dǎo)技術(shù)應(yīng)用 14
2.4 超導(dǎo)理論研究 15
2.4.1 金茲堡一朗道理論 15
2.4.2 BCS理論 17
2.4.3 RVB理論 18
2.4.3 本征超導(dǎo)理論 19
第3章 鉈系超導(dǎo)材料超導(dǎo)臨界溫度計算 23
3.1 本征超導(dǎo)態(tài)理論Tc計算公式 23
3.1.1 公式簡化 23
3.1.2 有關(guān)參數(shù)取法 23
3.2 鉈系超導(dǎo)材料的晶體結(jié)構(gòu) 24
3.2.1 Tl2Ba2Can-1CunO2n+4超導(dǎo)體的晶體結(jié)構(gòu) 25
3.2.2 TlBa2Can-1CunO2n+2.5超導(dǎo)體的晶體結(jié)構(gòu) 27
3.3 Tl2Ba2Can-1CunO2n+4超導(dǎo)體超導(dǎo)臨界溫度的計算 29
3.3.1 有效價電子數(shù)Ne和摩爾體積Va 29
3.3.2 有效價電子通道數(shù)neff 32
3.3.3 Tl2Ba2Can-1CunO2n+4超導(dǎo)臨界溫度Tc的計算 37
3.4 TlBa2Can-1CunO2n+2.5超導(dǎo)體超導(dǎo)臨界溫度Tc的計算 38
3.5 對計算結(jié)果的討論 42
3.5.1對的討論 43
第4章 鉈系超導(dǎo)體間隙球的計算 45
4.1 由金屬原子所構(gòu)成的晶體結(jié)構(gòu) 45
4.2 BCC晶體中的間隙 45
4.3 Tl2Ba2Can-1CunO2n+4晶體結(jié)構(gòu)間隙球的計算 47
4.4 對計算結(jié)果的討論 53
4.4.1 關(guān)于Tl2Ba2Can-1CunO2n+4摻雜的討論 53
第5章 結(jié)論 55
參考文獻 57
致謝 63
頁數(shù)：67 字?jǐn)?shù)：31202
摘 要
本文首先以鄒壯輝等人提出的本征超導(dǎo)理論和等效價鍵分析方法為基礎(chǔ)，計算了Tl2Ba2Can-1CunO2n+4 (n=1-4)和TlBa2Can-1CunO2n+2.5 (n=1-5)共9種材料的超導(dǎo)臨界溫度Tc，并對本征超導(dǎo)理論的Tc計算公式中的有效價電子通道數(shù)的取法作了優(yōu)化處理。這9種超導(dǎo)材料Tc值的計算結(jié)果，除Tl2Ba2Ca3Cu4O12和TlBa2Ca4Cu5O12.5的誤差偏大之外，其余7種超導(dǎo)體的計算Tc值和實驗值基本相吻合。對于Tl2Ba2Can-1CunO2n+4晶體，n=3時，=0.6312，該系列晶體的Tc達到最大值；對于TlBa2Can-1CunO2n+2.5晶體，n=4時，=0.6313，該系列晶體的Tc達到最大值。
以金屬原子的晶體結(jié)構(gòu)為氧化物晶胞的基本框架，計算Tl2Ba2Can-1CunO2n+4晶體的間隙位置及間隙半徑，分析鉈系氧化物超導(dǎo)材料摻雜特點。計算結(jié)果表明：全部的氧原子都占據(jù)間隙半徑較大的八面體間隙位置，計算值與實際相吻合；銅氧五面體的頂氧占據(jù)著晶格中最大的間隙位置，間隙球最有可能占據(jù)該位置，摻F的實驗工作已經(jīng)證實了這一規(guī)律[56-60]。另外，從尺寸因素和摻雜元素能否提供有效價電子兩個因素出發(fā)，討論摻雜后超導(dǎo)體Tc的變化，得出結(jié)論：F-, Ga+, In+, Tl+, Pb2+, Sn2+, Ge2+, C2+, Sb3+, As3+, Bi3+, N3+滿足尺寸因素，可能進入Tl2Ba2Can-1CunO2n+4晶格中，占據(jù)間隙位置，并且能夠提供有效價電子，有利于提高材料的Tc值。關(guān)鍵詞：本征超導(dǎo)態(tài)理論，超導(dǎo)臨界溫度，TBCCO，間隙球，摻雜
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 錄
任務(wù)書 i
中文摘要 ii
ABSTRACT iii
第1章 緒論 1
1.1 超導(dǎo)體的性質(zhì) 1
1.1.1 超導(dǎo)電性的發(fā)現(xiàn) 1
1.1.2 零電阻性 1
1.1.3 臨界磁場和臨界電流 1
1.1.4 邁斯納效應(yīng) 2
1.1.5 約瑟夫森效應(yīng) 2
1.1.6 同位素效應(yīng) 3
1.1.7 能隙效應(yīng) 3
1.2 課題研究方向和主要內(nèi)容 3
1.3 課題研究意義 4
第2章 超導(dǎo)研究的國內(nèi)外進展 7
2.1 超導(dǎo)材料實驗研究 7
2.2 實用化高溫超導(dǎo)材料研究 10
2.2.1 薄膜 10
2.2.2 塊材 11
2.2.3 帶材 12
2.3 高溫超導(dǎo)技術(shù)應(yīng)用 14
2.4 超導(dǎo)理論研究 15
2.4.1 金茲堡一朗道理論 15
2.4.2 BCS理論 17
2.4.3 RVB理論 18
2.4.3 本征超導(dǎo)理論 19
第3章 鉈系超導(dǎo)材料超導(dǎo)臨界溫度計算 23
3.1 本征超導(dǎo)態(tài)理論Tc計算公式 23
3.1.1 公式簡化 23
3.1.2 有關(guān)參數(shù)取法 23
3.2 鉈系超導(dǎo)材料的晶體結(jié)構(gòu) 24
3.2.1 Tl2Ba2Can-1CunO2n+4超導(dǎo)體的晶體結(jié)構(gòu) 25
3.2.2 TlBa2Can-1CunO2n+2.5超導(dǎo)體的晶體結(jié)構(gòu) 27
3.3 Tl2Ba2Can-1CunO2n+4超導(dǎo)體超導(dǎo)臨界溫度的計算 29
3.3.1 有效價電子數(shù)Ne和摩爾體積Va 29
3.3.2 有效價電子通道數(shù)neff 32
3.3.3 Tl2Ba2Can-1CunO2n+4超導(dǎo)臨界溫度Tc的計算 37
3.4 TlBa2Can-1CunO2n+2.5超導(dǎo)體超導(dǎo)臨界溫度Tc的計算 38
3.5 對計算結(jié)果的討論 42
3.5.1對的討論 43
第4章 鉈系超導(dǎo)體間隙球的計算 45
4.1 由金屬原子所構(gòu)成的晶體結(jié)構(gòu) 45
4.2 BCC晶體中的間隙 45
4.3 Tl2Ba2Can-1CunO2n+4晶體結(jié)構(gòu)間隙球的計算 47
4.4 對計算結(jié)果的討論 53
4.4.1 關(guān)于Tl2Ba2Can-1CunO2n+4摻雜的討論 53
第5章 結(jié)論 55
參考文獻 57
致謝 63
