文章信息/Info

Title:

The Analysis of the Bi-2212 Superconducting Mechanism and the reason of H2S Zero-Resistance Phenomenon by First Principle Calculations

作者:

盧天倪; 孫昱艷; 齊銘; 周廉

西安交通大學(xué)材料金屬材料強度國家重點實驗室， 西北有色金屬研究院超導(dǎo)材料研究所， 西安建筑科技大學(xué)，西安航空學(xué)院

Author(s):

LU Tianni;  SUN Yuyan;  QI Ming;  ZHOU Lian

State key Laboratory for Mechanical behavior of Materials, Xi’an Jiaotong Unversity; SMRC, Northwest Institute for Nonferrous Metal Research; Xi’an University of Architecture and Technology; Xi’an Aeronautical University

關(guān)鍵詞:

H2S; Bi-2212摻雜; 分波態(tài)密度譜; 電子團聚; 第一性原理計算

Keywords:

H2S;  Bi-2212 doping;  Partial density of states;  Electronic reunion;  First principle calculation

DOI:

10.7502/j.issn.1674-3962.2017.05.04

文獻標志碼:

A

摘要:

本文利用第一性原理分別對摻雜的Bi-2212高溫超導(dǎo)材料以及高壓下的H2S分子中各元素的分波態(tài)密度譜（PDOS）進行了計算。根據(jù)計算結(jié)果對Bi-2212的超導(dǎo)轉(zhuǎn)變溫度Tc隨摻雜含量改變而變化以及H2S在高壓下的零電阻現(xiàn)象進行了分析。在Bi-2212超導(dǎo)材料處于最佳摻雜含量時，電子能量接近于費米面附近的超導(dǎo)贗能隙從而降低了形成超導(dǎo)電子對所需的凝聚能，因此這些電子轉(zhuǎn)變?yōu)槌瑢?dǎo)電子對。另外，靠近費米面處的電子態(tài)密度在最佳摻雜量時達到最大值，即能夠被誘導(dǎo)為庫伯對的電子數(shù)量增多，在上述兩方面的共同作用下，電子在較高的溫度下能夠更容易轉(zhuǎn)變?yōu)槌瑢?dǎo)電子對，因此超導(dǎo)轉(zhuǎn)變溫度提高。本文還對高壓下的H2S晶體的PDOS譜進行了計算，根據(jù)計算的結(jié)果，高壓下的H2S由于晶格的收縮破壞了原子之間的成鍵，使得電子的分布已經(jīng)不滿足泡利不相容原理，而是以一種類似于“團聚”的形式存在。當對高壓下的H2S加載電壓后，這些“團聚”的電子能夠作為載流子移動從而形成電流，在此過程中，電子之間很難發(fā)生碰撞，其總動量的改變量可以認為是零，這是造成高壓下的H2S能夠在室溫范圍內(nèi)表現(xiàn)出“零電阻”現(xiàn)象的成因。

Abstract:

In this paper, the Partial Density of States (PDOS) of each element in doped Bi-2212 high temperature superconductor and H2S under high pressure is calculated by the first principle. According to the calculation results, we analysis the phenomenon that the critical temperature (Tc) of high temperature superconductor (HTS) Bi-2212 varies with doping content changing. When the Bi-2212 doping content is optimal, the electron energy is near the superconducting constrain gap, also the cohesive energy that the Cooper Pair electrons becoming needed is decreasing, so these electrons can turn into the superconducting cooper pairs more easily under the optimal content. In addition, with the optimal doping content, the densities of the superconductive electronics near Fermi surface increase to the maximum, which causes the number of becoming Cooper Pair electrons is increasing. Base on the two factors discussing above, the electrons can be induced to the superconducting electrons under higher temperature, thus the transition temperature of Bi-2212 increases. Last, this paper also discussed the calculation of the H2S under high pressure, it is known from the calculating results that the bond between the atoms can be destroyed because of the lattice contraction under high pressure. We speculate that the distribution of the electrons does not satisfy the Pauli Exclusion Principle under high pressure, but in a form liking "crowded". When the H2S is loaded voltage under high pressure, the "crowded" electrons can move as the carrier and form the electronic current, in the processing, due to the collision does not occur between electrons, thus the variation of the electron momentum is zero, so the H2S shows the zero resistance phenomenon in the Room temperature under high pressure.