Disorder-Induced Shift of Condensation Temperature for Dilute Trapped Bose Gases
2022年自考专业(英语)英语科技文选考试真题及答案37
2022年自考专业(英语)英语科技文选考试真题及答案一、阅读理解题Directions: Read through the following passages. Choose the best answer and put the letter in the bracket. (20%)1、 (A) With the recent award of the Nobel Prize in physics, the spectacular work on Bose-Einstein condensation in a dilute gas of atoms has been honored. In such a Bose-Einstein condensate, close to temperatures of absolute zero, the atoms lose their individuality and a wave-like state of matter is created that can be compared in many ways to laser light. Based on such a Bose-Einstein condensate researchers in Munich together with a colleague from the ETH Zurich have now been able to reach a new state of matter in atomic physics. In order to reach this new phase for ultracold atoms, the scientists store a Bose-Einstein condensate in a three-dimensional lattice of microscopic light traps. By increasing the strength of the lattice, the researchers are able to dramatically alter the properties of the gas of atoms and can induce a quantum phase transition from the superfluid phase of a Bose-Einsteincondensate to a Mott insulator phase. In this new state of matter it should now be possible to investigate fundamental problems of solid-state physics, quantum optics and atomic physics. For a weak optical lattice the atoms form a superfluid phase of a Bose-Einstein condensate. In this phase, each atom is spread out over the entire lattice in a wave-like manner as predicted by quantum mechanics. The gas of atoms may then move freely through the lattice. For a strong optical lattice the researchers observe a transition to an insulating phase, with an exact number of atoms at each lattice site. Now the movement of the atoms through the lattice is blocked due to therepulsive interactions between them. Some physicists have been able to show that it is possible to reversibly cross the phase transition between these two states of matter. The transition is called a quantum phase transition because it is driven by quantum fluctuations and can take place even at temperatures of absolute zero. These quantum fluctuations are a direct consequence of Heisenberg’s uncertainty relation. Normally phase transitions are driven by thermal fluctuations, which are absent at zero temperature. With their experiment, the researchers in Munich have been able to enter a new phase in the physics of ultracold atoms. In the Mott insulator state theatoms can no longer be described by the highly successful theories for Bose-Einstein condensates. Now theories are required that take into account the dominating interactions between the atoms and which are far less understood. Here the Mott insulator state may help in solving fundamental questions of strongly correlated systems, which are the basis for our understanding of superconductivity. Furthermore, the Mott insulator state opens many exciting perspectives for precision matter-wave interferometry and quantum computing.What does the passage mainly discuss?A.Bose-Einstein condensation.B.Quantum phase transitions.C.The Mott insulator state.D.Optical lattices.2、What will the scientists possibly do by reaching the new state of matter in atomic physics?A.Store a Bose-Einstein condensate in three-dimensional lattice of microscopic light traps.B.Increase the strength of the lattice.C.Alter the properties of the gas of atoms.D.Examine fundamental problems of atomic physics.3、Which of the following is NOT mentioned in relation to aweak optical lattice?A.The atoms form a superfluid phase of a Bose-Einstein condensate.B.Each atom is spread out over the entire lattice.C.The gas of atoms may move freely through the lattice.D.The superfluid phase changes into an insulating phase.4、What can be said about the quantum phase transition?A.It can take place at temperatures of absolute zero.B.It cannot take place above the temperatures of absolute zero.C.It is driven by thermal fluctuations.D.It is driven by the repulsive interactions between atoms.5、The author implies all the following about the Mott insulator state EXCEPT that______.A.the theory of Bose-Einstein condensation can’t possibly account for the atoms in the Mott insulator stateB.not much is known about the dominating interactions between the atoms in the Mott insulator stateC.it offers new approaches to exact quantum computingD.it forms a superfluid phase of a Bose-Einstein condensate6、 (B) Gene therapy and gene-based drugs are two ways we would benefit from our growing mastery of genetic science. But therewill be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the c oming years. While it’s true that just about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churning out stomach acid or your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy, when so-called stem cells haven’t begun to specialize. Most diseases involve the death of healthy cells—brain cells in Alzheimer’s, cardiac cells in heart disease, pancreatic cells in diabetes, to name a few; if doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue. It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to grow into neural, gut, muscle and bone cells. The process still can’t be controlled, and may have unforeseen limitations; but if efforts to understand and master stem-cell development prove successful, doctors will have a therapeutic tool of incredible power. The same applies to cloning, whichis really just the other side of the coin; true cloning, as first shown, with the sheep Dolly two years ago, involves taking a developed cell and reactivating the genome within, resenting its developmental instructions to a pristine state. Once that happens, the rejuvenated cell can develop into a full-fledged animal, genetically identical to its parent. For agriculture, in which purely physical characteristics like milk production in a cow or low fat in a hog have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what Ian Wilmut did for Dolly, and other creatures are bound to join the cloned menagerie in the coming year. Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could give doctors exactly the same advantages they would get from stem cells: the potential to make healthy body tissues of all sorts. And thus to cure disease.That could prove to be a true “miracle cu re”.What is the passage mainly about?A.Tomorrow’s tissue factory.B.A terrific boon to medicine.C.Human cloning.D.Genetic research.7、 According to the passage, it can be inferred that which of the following reflects the author’s opinion?A.There will inevitably be human cloning in the coming year.B.The potential to make healthy body tissues is undoubtedly a boon to human beings.C.It is illegal to clone any kind of creatures in the world.D.It is legal to clone any kind of creatures in the world except human.8、Which of the following is NOT true according to the passage?A.Nearly every cell in the human brain has the instructions to make a complete human.B.It is impossible for a cell in your nose to turn into a kidney.C.It is possible to turn out healthy replacement tissues with isolated stem cells.D.There will certainly appear some new kind of cloned animal in the near future.9、All of the following are steps involved in true cloning EXCEPT_______.A.selecting a stem cellB.taking a developed cellC.reactivating the genome within the developed cellD.resetting the developmental instructions in the cell to its original state10、The word “rejuvenated” in para. 5 is closest in meaning to_______.A.rescuedB.reactivatedC.recalledD.regulated参考答案：【一、阅读理解题】1~5CDDAD6~10DBBA。
凝聚态物理相关诺贝尔奖
凝聚态物理相关诺贝尔化学奖1970-凝聚态物理相关诺贝尔物理学奖1970-“他们联合创立了微观理论，即常说的”"for their jointly developed theory ofsuperconductivity,“发现和的”"for their experimental discoveries regardingtunneling phenomena in semiconductors andsuperconductors, respectively"“他理论上预测出通过隧道势垒的超电流的性质，些通常被称为的现象”"for his theoretical predictions of the properties ofathose phenomena which are generally known as theJosephson effect"“对磁性和无序体系电子结构的基础性理论研究”"for their fundamental theoretical investigationsof the electronic structure of magnetic anddisordered systems"“低温物理领域的基本发明和发现”"for his basic inventions and discoveries in thearea of low-temperature physics"“对与相转变有关的临界现象理论的贡献”"for his theory for critical phenomena in connection withphase transitions"“发现”"for“电子光学的基础工作和设计了第一台”"forthe design of the first electron microscope"“研制”"for their design of the scanning tunnelingmicroscope"“在发现的方面的突破”"forof superconductivity in ceramic materials"“发现研究简单系统中有序现象的方法可以被推广到比较复杂的物质形式，特别是推广到和的研究中”"for discovering that methods developed for studying ordermore complex forms of matter, in particular to liquid crystals and polymers"“发现了在里的”"for their discovery of superfluidity inhelium-3"“发展了用于高速电子学和的”"for developing semiconductor heterostructuresused in high-speed- and optoelectronics"“在发明中所做的贡献”"for his part in the invention of the integratedcircuit"“在碱性原子稀薄气体的方面取得的成就，性质的早期基础性研究”"for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates"“对和理论做出的先驱性贡献”"for pioneering contributions to the theory ofsuperconductors and superfluids"“发现”"for the discovery of giant magnetoresistance"“在光学通信领域光在中传输方面的突破性成就”"for groundbreaking achievements concerning thetransmission of light in fibers for opticalcommunication"“发明成像器件”"for–“在二维材料的开创性实验”"for groundbreaking experiments regarding the two-dimensional material graphene"。
囚禁离子内态的相干导致声子场的压缩
中 图分 类 号 Ｏ １ ． ４３ １
Ｓｑ ｅ ｚｎ ｆＰ ｏ ｏ ｉｌｓ Ｉｄ ｃ ｄ ｂ ｈ ｒ ｎ ｅ ｏ ｎｅ ｎ ｌ ｕ ｅ ｉｇ ｏ ｈ ｎ ｎ Ｆｅｄ ｎ ｕ ｅ ｙ Ｃｏ ｅ ｅ ｃ ｆＩｔ ｒ ａ Ｓｔｔ ｓ ｏ ａ ｐ ｄ Ｉ ｎ ａｅ ｆ Ｔｒ ｐ ｅ ｏ ｓ
ｍｉｅ ｔｔ ｄ ｔ ｅｐ ｏ ｏ ｅｄ ｉ ａ ｕ ｍ ｔｔ ｔｅ ｅ ｏｖ ｄ ｓａｅ ｏ ｈ ｈ ｎ ｎ ｆｅｄ ｄ ｅ ｏ ｐ ｅ ｒｓ ｕ ｅ ｉｇ；Ｈｏ ｘ ｄ ｓａｅ ａ ｈ ｈ ｎ ｎ ｆ ｌ ｎ ａ ｖ ｃ ｕ ｓａｅ，ｈ ｖ ｌｅ ｔｔ ｆｔ ｅｐ ｏ ｏ ｌ ｏ ｓｎ ｔａ ｐ ａ ｑ ｅ ｚｎ ｎ ｉ ｉ ｗ－
ｅ ｅ ， ｅ ｈ ｎ ｅｎ ｔｔ ｓｉ ｉｉ ｌ ｎ ａｃ ｈ ｒ ｎ ｕ ｅ ｐ ｓｔｏ ｕ ｅ ｓａｅａ ｄ ｔｅ ｐ ｏ ｏ ｅｄ ｉ ａ ｕ ｍ ｔｔ ，ｈ ｖ ｒ ｗｈ ｎ ｔｅ ｉ ｔｒ ａ ｓａｅ ｉ ｎ ｔ ｙ ｉ ｏ ｅ ｅ ｔｓ ｐ ｒ ｏ ｉ ｎ ｐ ｒ ｔｔ ｎ ｈ ｈ ｎ ｎ ｆ ｌ ｎ ａｖ ｃ ｕ ｓａｅ ｔ ｅ ｌ ｌ ａ ｉ ｉ ｅ ｏｖ ｄ ｓａｅ ｏ ｈ ｈ ｎ ｎ ｆｅｄ ｓ ｏ ｑ ｅ ｚｎ Ｕｎ ｒｐ ｐ ｒｉ ｉ ａ ｏ ｄｔｏ ｓ，ｈ ｑ ｅ ｚｎ ｓｐ ｒｉｔｎ ｄ ｐ ｒｏ ｉ ｖ ｌｅ ｔｔ ｆｔ ｅｐ ｏ ｏ ｌ ｈ ｗｓｓ ｕ ｅ ｉｇ． ｄｅ ｒ ｅ ｎｔｌ ｃ ｎ ｉ ｎ ｔ ｅ ｓ ｕ ｅ ｉ ｇｉ ｅｓｓｅ ｔａ ｅ ｄ ｃ ｉ ｏ ｉ ｉ ｎ ｉ
NBTIPMOS薄栅氧PMOS器件的HCI效应和NBTI效应
可靠性：PMOS 薄栅氧PMOS 器件的HCI 效应和NBTI 效应《半导体制造》 2006 年 10 月刊作者： Joyce Zhou 、 Jeff Wu、 Jack Chen 、 Wei-Ting Kary Chien, 中芯国际随着 CMOS 晶体管尺寸的不断微缩，人们越来越关注 PMOS HCI（热载流子注入）可靠性问题。
本文对薄栅氧PM OS 晶体管的可靠性进行了准确的表征，并且深入研究了其衰减机制。
此外，我们还对引起PMOS 器件衰减的 N BTI（负偏压温度不稳定性）效应进行了解释说明。
对 PMOS 而言，最坏的衰减条件与 Vg 大小非常相关。
为此，我们提出一种方法以证明 PMOS 衰减是在较大Vg 条件下由HCI 效应导致的漏极缺陷引起的，它与NBTI 效应完全不同。
此外，我们还分别解释了HCI 和 NBTI 效应的机理。
最后，我们研究了 HCI和NBTI 的综合效应。
在 HCI 和NBTI的综合作用下，超薄栅氧 PMOS 器件参数的衰减程度比单独的 HCI 或 NBTI 效应要严重得多。
为了找到薄栅氧 PMOS 器件 HCI效应的最坏条件，实验中我们对 1.2V和1.5V 短沟道 PMOS 器件进行了测试。
我们提出了一种在较高栅电场下区分 HCI 效应和 NBTI 效应的方法。
此外，我们还对这两种效应（即 HCI 和 NBTI）导致的器件参数偏移之间的相关性进行了研究，并且探讨了 HCI-NBTI 综合效应对薄栅氧 PMOS 器件可靠性的严重影响。
下一节我们将介绍 HCI 的最坏条件。
为了检测 HCI 效应引起的漏极损伤问题，我们在下一节中引入了“偏移”参数（Offset）。
然后，我们对非均匀 NBTI 效应进行了描述。
薄栅氧 PMOS 器件 HCI 效应的最坏条件正如JEDEC-60 提到的那样，在施加大小为 Vg 的栅偏压条件下， p沟道器件的参数变化程度最大，此时栅电流也处于最大值（Ig）[1] 。
激光诱导钛合金等离子体电子温度和电子密度的时间分辨测量
第23 卷第 1 期2024 年 3 月宁夏工程技术Vol.23 No.1 Ningxia Engineering Technology Mar. 2024激光诱导钛合金等离子体电子温度和电子密度的时间分辨测量胡桢麟1，高阳2，林楠1*，郭连波3（1.中国科学院上海光学精密机械研究所，上海201800； 2.华东理工大学机械与动力工程学院，上海200237；3.华中科技大学武汉光电国家研究中心，湖北武汉430074）摘要：以波长为532 nm的纳秒脉冲激光器为激发源，使用中阶梯光栅光谱仪和增强电荷耦合器件（ICCD）获得了激光诱导钛合金等离子体的时间分辨发射光谱；基于发射光谱，利用玻尔兹曼图法和萨哈-玻尔兹曼图法计算了等离子体电子温度；采用斯塔克展宽法计算了电子密度。
研究结果表明，相较于玻尔兹曼图法，萨哈-玻尔兹曼图法可提供更为准确的电子温度计算结果。
此外，光谱采集门宽的增大会导致等离子体电子温度和电子密度计算值的减小。
以上研究结果为钛合金的激光诱导击穿光谱（LIBS）分析提供了实验指导。
关键词：钛合金；激光诱导等离子体；电子温度；电子密度；时间分辨测量；激光诱导击穿光谱中图分类号：O433.4 文献标志码：A激光诱导击穿光谱（LIBS）技术是一种热门的元素成分分析技术，其原理是采用高能量的脉冲激光聚焦烧蚀待测样品表面，诱导产生等离子体，然后通过等离子体的发射光谱对样品中的元素种类及含量进行分析［1-3］。
由于LIBS技术具有无需或简单制样，可实现原位、实时、远程和全元素检测等优点，目前已被应用于冶金［4］、燃煤［5］、核工业［6］、环保［7］、勘探［8］和火星探测［9］等领域。
在冶金领域中，LIBS技术常用于合金样品的元素成分分析，高能量脉冲激光与固体的相互作用会经历加热、熔化、气化和电离等复杂过程，最终诱导产生等离子体。
产生的等离子体在冷却过程中其电子温度与电子密度等特性在微秒尺度上快速变化，进而会影响LIBS光谱的成分、强度与稳定性等特性。
玻色-爱因斯坦凝聚理论研究
南京师范大学泰州学院毕业论文（设计）（ 2014 届）题目：＿＿玻色-爱因斯坦凝聚理论研究＿院（系、部）：信息工程学院＿＿＿＿专业：物理学（师范）＿＿＿＿姓名：严加林＿＿＿＿＿＿学号： 12100134 ＿＿＿＿＿指导教师：朱庆利＿＿＿＿南京师范大学泰州学院教务处制摘要玻色-爱因斯坦凝聚(玻色—爱因斯坦凝聚)是科学巨匠爱因斯坦在80年前预言的一种新物态。
这里的“凝聚”与日常生活中的凝聚不同，它表示原来不同状态的原子突然“凝聚”到同一状态（一般是基态）。
即处于不同状态的原子“凝聚”到了同一种状态。
形象地说，这就像让无数原子“齐声歌唱”，其行为就好像一个玻色子的放大，可以想象着给我们理解微观世界带来了什么。
本文针对玻色-爱因斯坦凝聚这一课题，综述了玻色-爱因斯坦凝聚理论的诞生和发展、概念及其形成条件。
在凝聚体实现发面，随着科学技术的发展，我们实现了玻色-爱因斯坦凝聚。
1995年，随着 JILA 小组、MIT小组、Rice大学的试验成功，玻色-爱因斯坦凝聚到热浪被推上了高潮。
本文中还将介绍一些玻色—爱因斯坦凝聚的实验和国内外的研究动态，最后展望了其发展前景。
关键词：玻色-爱因斯坦凝聚，激光冷却与囚禁，原子激光AbstractBose Einstein condensation (BEC) is a new material predicted by science master Einstein in 80 years ago. Here the "cohesion" is different from condensation in everyday life. It says that different states of atomic suddenly "condensed" to the same state (usually the ground state). In different states of atoms "condensed" to the same state. Figure ground says, this is like so many atomic "sing in union", amplifying its behavior as a boson, you can imagine what brings to our understanding of the microscopic world. According to Bose Einstein condensates of this topic, reviews the Bose Einstein condensates birth and development, theory and its formation conditions. In the realization of yeast aggregates, with the development of science and technology, we realize the Bose Einstein condensation. In 1995, with the test of JILA group, MIT group, Rice University's success, Bose Einstein condensates to heat was pushed to the climax. This paper will also introduce some of Bose Einstein condensation in the experiment and research dynamic status, and its development prospects.Keywords: Bose Einstein condensation, laser cooling and trapping, Atom laser目录摘要 (1)Abstract (II)第一章引言 (1)1.1 冷原子 (1)1.2 玻色-爱因斯坦凝聚 (1)第二章玻色-爱因斯坦凝聚的研究历史 (2)2.1 玻色-爱因斯坦凝聚的诞生 (2)2.2玻色-爱因斯坦凝聚的发展 (2)第三章玻色-爱因斯坦凝聚的概念及形成条件 (5)3.1 玻色-爱因斯坦凝聚的概念 (5)3.2 实现玻色-爱因斯坦凝聚的物理条件 (6)第四章玻色-爱因斯坦凝聚的实验简介 (8)4.1 实现玻色-爱因斯坦凝聚的探索 (8)4.2 Colorado大学的JILA小组的工作 (10)4.3 MIT小组的工作 (10)4.4 Rice大学的工作 (11)4.5 其他小组的工作 (12)第五章玻色-爱因斯坦凝聚的研究动态 (14)4.1 国外动态 (14)4.1 国内动态 (15)第六章玻色-爱因斯坦凝聚的前景展望 (17)结束语 (18)致谢 (19)参考文献 (20)第一章引言1.1冷原子近年来，超冷原子物理学蓬勃的发展起来。
Rb85能级图
1 Introduction
3
1 Introductiቤተ መጻሕፍቲ ባይዱn
In this reference we present many of the physical and optical properties of 85 Rb that are relevant to various quantum optics experiments. In particular, we give parameters that are useful in treating the mechanical effects of light on 85 Rb atoms. The measured numbers are given with their original references, and the calculated numbers are presented with an overview of their calculation along with references to more comprehensive discussions of their underlying theory. At present, this document is not a critical review of experimental data, nor is it even guaranteed to be correct; for any numbers critical to your research, you should consult the original references. We also present a detailed discussion of the calculation of fluorescence scattering rates, because this topic is often not treated clearly in the literature. More details and derivations regarding the theoretical formalism here may be found in Ref. [1]. The current version of this document is available at /alkalidata, along with “Cesium D Line Data,” “Sodium D Line Data,” and “Rubidium 87 D Line Data.” This is the only permanent URL for this document at present; please do not link to any others. Please send comments, corrections, and suggestions to dsteck@.
AHE
Parallel transport of vector v on curved surface
Constrain v in local tangent plane; no rotation about e3
constraint
angle
Parallel transport
e3 x dv = 0
v acquires geometric angle α relative to local e1
ρ xy = R0 H + ρ ′ xy
′ ρ xy = Rs M
A brief History of the Anomalous Hall Effect 1890? Observation of AHE in Ni by Erwin Hall 1935 Pugh showed ρxy’ ~ M 1954 Karplus Luttinger; transport theory on lattice Discovered anomalous velocity v = eE x Ω. Earliest example of Berry-phase physics in solids. 1955 Smit introduced skew-scattering model (semi-classical). Expts confusing 1958-1964 Adams, Blount, Luttinger Elaborations of anomalous velocity in KL theory 1962 Kondo, Marazana Applied skew-scattering model to rare-earth magnets (s-f model) but RH off by many orders of magnitude. 1970’s Berger Side-jump model (extrinsic effect) 1973 Nozieres Lewiner AHE in semiconductor. Recover Yafet result (CESR) 1975-85 Expt. support for skew-scattering in dilute Kondo systems (param. host). Luttinger theory recedes. 1983 Berry phase theorem. Topological theories of Hall effect 19991999-2003 Berry phase derivation of Luttinger velocity (Onoda, Nagaosa, Niu, Jungwirth, MacDonald, Murakami, Zhang, Haldane)
mse-2
Wieman said: ``I discovered that I'm not nearly as excited about winning the prize as I was about seeing the Bose-Einstein condensate for the first time.''
The condensates he managed to produce contained more atoms and could therefore be used to investigate the phenomenon further.
``I hoped that one day this might happen, but I was really thinking along the lines of 20 years later and not six,'' said Cornell.
Bose-Einstein condensate (BEC, 波 色－愛因斯坦冷凝物)
Eric A. Cornell （39）， Wolfgang Ketterle（43） ，Carl E. Wieman（50）
Bose-Einstein condensate
1995, Cornell and Wieman a pure condensate of about 2 000 rubidium atoms at 20 nK (nanokelvin), Ketterle：sodium atoms.
鍵結力與能量
吸引力、排斥力，淨力 吸引能、排斥能，淨能
鍵結能
力、能量與原子間距離曲線
鍵結能大：熔點高
室溫：固體、液體、氣體 力與原子間距離曲線：剛硬
（凝聚态物理专业优秀论文）双能带结构对MGBLT2GT磁通钉扎的影响
东南大学硕士学位论文第二章ＭｇＢｚ双能带结构的特点§２．１引言在钉扎力的理论计算中，会用到～些实验能直接测量的物理量。
所以研究ＭｇＢ２的钉扎力，就要对其双能带结构有清晰的了解。
ＭｇＢ２是一种典型的非理想第二类超导体，它具有很高的临界温度（Ｔｏ＝３９Ｋ）和和较大的Ｇｉｎｚｂｕｒｇ－Ｌａｎｄａｕ参数【１】（ｇ－＝２６）。
ＭｇＢ２的费米面是由两维的。
带和三维的ｎ带组成的ｆ２－５】，这个结论已经由扫描隧道光谱Ｍ、比热‘叫、点接触谱‘ｌＯｍ］、拉曼光谱［…、光发射谱【１’…、核磁共振‘“，平面热电导㈣及中子散射的实验【１１证实。
由实验，可以得到ＭｇＳ２（主要是单晶样品）双能带结构的一些特点：两个能带的各向异性“ｇ－１９］、涡旋图像叫、ｌ艋界场Ⅲ垮等。
通过分析计算，可以得到对钉扎力计算有用的量，例如上临界磁场、两个能带的贡献比等等。
下面详细介绍ＭｇＢ２双能带结构的特点。
§２．２ＭｇＢ２的晶体结构一般来说，固体物质的原子结构决定它的化学性质和许多与其相关的物理特性。
在研究ＭｇＢ２双能带结构特点前，先对ＭｇＢ２超导体的晶体结构进行简单的介绍，这样对理解ＭｇＢ２的超导机制以及预测其性质特点都具有极其重要的意义。
我们参考了已有的研究成果，将ＭｇＢ２的晶体结构加以简单的介绍：图２—１ＭｇＢ２的晶体结构第二章Ｍｇａ２双能带结构的特点图２—１给出了ＭｇＢ２的晶体结构示意图口１。
ＭｇＳ２的结构属六方晶系，其空间群代码是１９１（符号：Ｐ／６ｍａ）。
由ｘ射线及早期的结构分析脚１得出的晶格参数分别是：ａ＝Ｏ．３０８６Ｉ吼、ｏ＝０．３５２４ｎｌｌｌ。
ＭｇＢ２的原胞中含有三个原子，由一个镁原子和两个硼原子组成。
图中小球代表Ｂ原子，大球代表Ｍｇ原子。
Ｍｇ原子形成的六角密堆积层和Ｂ原子形成的类石墨结构层交替分布，Ｍｇ原予和Ｂ原子分别占据Ｉａ和２ｄ位置，每个固体物理学原胞含有一个形式结构的单元。
与石墨类似，ＭｇＢ２中的Ｂ—＿Ｂ链显示出很强的各向异性，这是由于Ｂ原子之间的层间距离比层内距离大的多的缘故。