Chapter 542: Prelude to the storm

Three hours,
Including theoretical aspects, computational aspects, and even the next experimental part, Fan Zhilong felt that Xu Mang once again re-set the three-hour time concept. The original three hours can do so much content, and it will even change one up to eight. Prophecy of more than ten years.
In this manuscript, first of all, two methods to obtain Weyl semimetal are obtained from theory. One is to break the time reversal and maintain the symmetry of the center inversion, and the other is to maintain the time reversal symmetry and break the center of the symmetry play.
According to the first type, Xu Mang gives the materials for pyrochlore structure, spinel structure, ordinary insulating materials, topological insulating materials; if according to the second type, Se and Te crystals synthesized under pressure provide negative BiSb and ZrTe as evidence of the possibility of magnetoresistance, as well as Dirac semimetals.
According to Xu Mang’s conclusion, the magnetic domains and the destruction of translational symmetry caused by the magnetic atoms in the system hinder the study of the intrinsic properties of foreign fermions in the experiment, and the preparation of materials is relatively difficult.
So Xu Mang chose the second method to find a non-magnetic material.
TaAs crystals have become the best choice,
The theory seems to be true, but it lacks too much evidence, the kind of direct evidence, and the numerical proof.
And his second principle calculation solved all the previous doubts, and it is also a little bit contrary to the previous theory. This material has no center inversion but maintains the time reversal symmetry, and can be synthesized naturally without mixing. Miscellaneous and other detailed and complicated control.
The more important thing is that there is no complexity such as magnetic domains brought by magnetic materials. You can directly use the equipment for experimental observation to facilitate the most direct evidence.
This...
Is this the result of three hours? !
Xu Mang redefines the concept of three hours.
"Xu Mang?"
"Really... how did you do it?" Fan Zhilong asked with an incredulous look: "What did you do in your apartment? Fortunately, I have received higher education, and then I think you are God."
"Ha ha..."
"You are right. I am indeed God. It's just that I understand God's thinking from a scientific point of view." Xu Mang said with a smile on his face: "Unsurprisingly, TaAs crystals are Weyl semimetals. Prophecy that has lasted for more than 80 years will be broken."
"In my calculations... the lattice constants of TaAs crystals are a=3.44, c=11.64, showing a body-centered tetragonal structure, which belongs to a special space point group. There are 12 Weyl fermions with opposite chirals in the lattice momentum space. ."
"There are open Fermi arcs on the surface, and there are pairs of Weyl cones with linear cross-conical band structures inside." Xu Mang said seriously: "These typical electronic structures can be observed, and I It is obtained directly from the database."
Fan Zhilong did not speak, and kept looking at these contents. The excitement in his heart is unparalleled. If... if all of this is true, then an eighty-odd secret will really be broken, and this person will be Professor from the Department of Physics, Fuda.
but...
How to prepare such high-quality TaAs crystals?
"Xu Mang?"
"what?"
"Will you make this high-quality TaAs crystal?"
"No way!"
Suddenly,
The laboratory was silent, and the two looked at each other, seeing the embarrassment in each other's eyes.
This...
After discussing so much, they said the truth, and in the end, neither of them can prepare this material. This means that the previous theories are all for nothing. Even if the theory is correct, the calculation is accurate, and there is no real object to do research, everything is funny.
"Hey?"
"Director Liu?" Xu Mang asked cautiously: "Guess who I am? There is no reward for correct guessing."
"..."
With this kind of words, you can know if you think about it with your toes, but who else can Xu Mang be?
"I have caller ID!" Director Liu Guofang of the Department of Materials asked grimly: "What can I do with you? Listen to your tone...it seems to be in trouble."
"Hey..."
"I just want to ask if our materials department is capable of preparing TaAs crystals?" Xu Mang asked quietly, "A high-quality TaAs crystal."
"TaAs crystals?"
"This seems to be a matter of condensed matter?" Liu Guofang said solemnly: "But we should be able to prepare it. What do you want this material for suddenly?"
"Do not ask!"
"Ask is to change the world." Xu Mang said with a smile: "That's OK... it can be prepared. I will come to your office later. Let's discuss it and prepare high-quality TaAs crystals as soon as possible."
hang up,
Xu Mang glanced at Fan Zhilong: "It can be prepared. I will go to the office of Director Liu of the Department of Materials and finish this matter. Then I will use STM equipment to measure the surface electronic state with high precision, and then I will call it a day!"
"Tomorrow."
"See for yourself what time is already." Fan Zhilong reminded.
"Ouch?"
"Fuck... I'm going to buy some groceries, otherwise the tigress at home will have some special frying." Xu Mang put his manuscript into the bag and asked Fan Zhilong: "Professor Fan...you Say I am a great scientist, why am I so humiliated at home?"
"..."
"Who asked you to marry classmate Yang Xiaoman." Fan Zhilong said helplessly: "What kind of woman you marry will have to pay what price."
cost!
As expected, Professor Fan, who has been in the scientific research field for so long, hit the nail on the head... directly saw the root of the problem.
Xiaoman is very headstrong,
but...
Xu Mang sighed, and said with a look of lovelessness: "I'm not afraid of your joke, I just like this one myself."
Words fall,
Leave in a hurry.
The next day,
Xu Mang came to the material department building early, and stood at the door of Director Liu for a while, glanced at the fruit basket in his hand, after thinking about it, put it at the door, and then pushed in and saw Director Liu in the office.
"Director Liu?"
"Are you busy?" Xu Mang put on his trademark smile, walked up with a shameful expression, and stood opposite Liu Guofang.
"..."
Liu Guofang sighed, and said helplessly: "Xu Mang...Your current identity is different. Can you take the seriousness it deserves? Scientist Xu?"
"Can't change it."
"Jiangshan is easy to change, and nature is hard to change, and it can't be changed...unless you are reborn again." Xu Mang smiled: "Then what...can we talk about work first, and then about personality problem?"
"It's rare for you to cut directly to the topic for the first time." Liu Guofang asked, "Are there any relevant information?"
"Have!"
"Look over it." Xu Mang took out a stack of manuscript paper from his bag and handed it to Director Liu Guofang.
After receiving this manuscript, Liu Guofang glanced at it. Within a few minutes, he raised his head in surprise, and asked seriously: "You said that TaAs crystals are the Weyl semi-metallic materials predicted more than 80 years ago?"
"Correct!"
"Basically it is true." Xu Mang nodded: "If there are no problems with my calculations, as long as I prepare high-quality TaAs crystals, and then use my modified STM equipment for high-precision measurement, it is all right!"
Liu Guofang said solemnly: "I will make arrangements right away!"
Leave the materials department building,
Xu Mang's heart returned to peace. Director Liu Guofang promised to complete the preparation of high-quality TaAs crystals in the fastest time, the estimated time is about three days.
Three days...
Almost there!
Xu Mang calculated the time for the announcement of the June meeting. It will be released almost a week later. The unilateral resolution of the United States, the so-called Global Condensed Matter Alliance launch resolution, is the only organization missing from China.
Just think about it!
A broken organization is the same as it really is.
Xu Mang was very disgusted with this June meeting. The most important reason was that he participated in the whole process. Seeing the so-called technological hegemonism of those developed countries, there was a fire in his heart.
This flame is more ferocious than the last time I saw Xiaoman wearing sheep ears and goat clothes.
Ugh?
By the way...
Xu Mang suddenly came up with a bold idea. He wanted Xiaoman to go to COS Hancock. After all, the two are similar. Yang Xiaoman is the empress of the business world, and Hancock is called the Pirate Queen, but. .. Something seems to be wrong.
correct!
The body is a fatal flaw, Xiaoman... Forget it, it's tears if you talk too much!
night,
Always come quietly,
Xu Mang glanced at Xiaoman who was reading Weibo next to him, and asked cautiously: "Xiaoman...humiliated?"
Yang Xiaoman: (￣︿￣)
it has started!
This idiot started again!
It's true that you are not afraid of beating or scolding. Why is this stupid head so iron?
This night,
Xu Mang was very humiliated.
...
Institute of Condensed Matter,
this day,
The Weil Semimetal research team encountered a difficult problem. Based on the theoretical results... they needed to make a choice. Firstly, ordinary insulator materials and topological insulator materials, and secondly, ordinary insulators and topological insulators near the phase transition, breaking time inversion Or a symmetrical solid solution with the center inversion.
Both materials are possible, but the second one should be chosen after analysis, but... the calculation of the second one is too complicated and almost impossible to complete.
Professor Tian said that this problem has been tortured to the point of collapse. All kinds of evidence point to the second material, this non-magnetic material. However, how to correctly choose among many non-magnetic materials requires complicated calculations to get the result. .
At the same time... Reasonable deduction is also one of the conditions, and this step cannot be completed without any of the two.
finally,
Professor Tian could only find his friend, a domestic mathematics expert, hoping to cooperate with him to solve this part of the problem. However, the mathematics expert told Professor Tian that it would take at least a week.
A week?
One week is one week.
When solving this problem, the team members are not idle, they need to make various assumptions about the experiment so that they can be carried out quickly in the next steps.
"Speaking..."
"Which step is Professor Xu?" a master student from National Tsing Hua University asked: "Will it be faster than ours?"
"impossible!"
"I have contacted my high school classmates~EbookFREE.me~ He worked as a teaching assistant at Fuda. Recently, Professor Xu did not have his voice. It seems that the world has evaporated." A scientific graduate student said: "It is impossible to compare. Let’s do it faster, don’t worry... I bet."
At this time,
A girl said: "I think everyone should be mentally prepared. Maybe this is the tranquility before the storm... Usually there is nothing wrong before the storm, and suddenly there will be lightning and thunder."
No one spoke,
At this moment they knew they were going to race against time.
......
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