three hours,

Including theoretical aspects, calculation aspects, and even the following experimental part, Fan Zhilong felt that Xu Mang had once again redefined the concept of three hours. It turns out that so much content can be done in three hours, and it will even change an eight-hour time limit.

Prophecy for more than ten years.

In this manuscript, two methods for obtaining Weyl semimetals are first derived from theory. One is to break the time reversal while maintaining central inversion symmetry, and the other is to maintain time reversal symmetry and break central symmetry inversion.

play.

According to the first method, Xu Mang gave a list of materials including pyrochlore structure, spinel structure, ordinary insulating materials, and topological insulating materials. According to the second method, crystals synthesized under pressure may provide negative magnetoresistance.

sexual evidence, and Dirac semimetals.

According to Xu Mang's conclusion, the magnetic domains brought by magnetic atoms in the system and the destruction of translational symmetry by impurity atoms have hindered the study of the intrinsic properties of Weyl fermions in experiments, and the preparation of materials is relatively difficult.

So Xu Mang chose the second method to find a non-magnetic material.

Taas crystal has become the best choice,

The theory seems to be true, but it lacks too much evidence, direct evidence, and numerical proof.

His second principle calculation solved all the previous doubts, and was a little contrary to the previous theory. This material has no central inversion but maintains time reversal symmetry, and can be synthesized naturally without the need for doping.

Complex and detailed control.

What's more important is that there are no complications such as magnetic domains caused by magnetic materials, and the equipment can be directly used for experimental observations to obtain the most direct evidence.

this

This is the result of three hours?!

Xu Mang redefined the concept of three hours of time.

"Xu Mang?"

"Seriously, how did you do it?" Fan Zhilong asked with a look of disbelief: "What on earth did you do back in your apartment? Fortunately, I received higher education, and then I thought you were God.

"

"hehe"

"You are right, I am indeed God, but I am trying to understand God's thinking from a scientific perspective." Xu Mang said with a smile: "If nothing else, the TAAS crystal is a Weyl semimetal.

The prophecy that has lasted for more than 80 years will be broken."

"In my calculations, 44 and 1.64 have a body-centered tetragonal structure and belong to a special space point group. There are 12 Weyl fermions with opposite chirality in the lattice momentum space."

"There are open Fermi arcs on the surface, and there are pairs of Weyl cones with linear cross-cone band structures inside." Xu Mang said seriously: "These typical electronic structures can be observed, and we

It is obtained directly from the database."

Fan Zhilong didn't speak, and kept looking at these contents. The excitement in his heart was unparalleled. If all this is true, then a secret that has lasted for more than eighty years will really be broken, and this person will be from Fuda.

Professor in the Department of Physics.

but

How to prepare such high-quality TAAS crystals?

"Xu Mang?"

"ah?"

"Can you make this high quality taas crystal?"

"No way!"

Suddenly,

There was silence in the laboratory. The two looked at each other and saw the embarrassment in each other's eyes.

this

After so much discussion, everything was succinct, but it turned out that neither of them knew how to prepare this kind of material, which meant that the previous theories were all in vain. No matter how correct the theory was and how accurate the calculations were, without physical objects to do research, everything would be a joke.

"Hello?"

"Director Liu?" Xu Mang asked cautiously: "Guess who I am? There will be no reward for guessing correctly."

""

There is such a meanness in these words, you can tell by just thinking about it with your toes, who else could it be if it wasn't Xu Mang?

"I have caller ID!" Director Liu Guofang of the Department of Materials asked angrily: "What do you want from me? It sounds like you are in trouble."

"hey-hey"

"I just want to ask if our materials department has the ability to prepare TAAS crystals?" Xu Mang asked in a low voice: "A high-quality TAAS crystal."

"Taas crystal?"

"This seems to be something related to condensed matter, right?" Liu Guofang said seriously: "But we should be able to prepare it. What do you suddenly need this material for?"

"Don't ask!"

"Asking is changing the world." Xu Mang said with a smile: "As long as you can prepare it, I will come to your office later and we will discuss how to 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 Director Liu's office of the Department of Materials to get this matter done. Then I will use STM equipment to conduct high-precision measurements of the surface electronic states, and then call it a day!"

"Tomorrow."

"See for yourself what time it is." Fan Zhilong reminded.

"Ouch?"

"Damn it, I have to go buy groceries, otherwise the tigress at home will have her hair fried." Xu Mang put his manuscript into his bag and asked Fan Zhilong, "Professor Fan, you said I am a great scientist.

Why are you so humiliated at home?"

""

"Who asked you to marry classmate Yang Xiaoman?" Fan Zhilong said helplessly: "You have to pay a price for whatever kind of woman you marry."

cost!

As expected of Professor Fan, who has been in the scientific research community for so long, he saw the root of the problem directly.

Xiaoman is very willful,

but

Xu Mang sighed and said with a look of despair on his face: "I'm not afraid of your jokes, that's what I like."

The words fell,

Leave in a hurry.

The next day,

Xu Mang arrived at the Materials Department building early and stood for a while at the door of Director Liu. He glanced at the fruit basket in his hand, thought about it carefully and placed it at the door. Then he pushed the door open and saw Director Liu in the office.

"Director Liu?"

"Busy?" Xu Mang put on his signature smile, walked up with a mean look on his face, and stood opposite Liu Guofang.

""

Liu Guofang sighed and said helplessly: "Xu Mang, your current status is different. Can you show some seriousness as you should? Scientist at Xu University?"

"It can't be changed."

"Nature is easy to change but hard to change. If you can't change it, you have to be reincarnated all over again." Xu Mang said with a smile: "Then can we talk about work first, and then talk about personality issues?"

"It's rare that you get to the point directly for the first time." Liu Guofang asked: "Is there any relevant information?"

"have!"

"Take a look." Xu Mang took out a stack of manuscript paper from his bag and handed it to Director Liu Guofang.

Taking the manuscript, Liu Guofang glanced at it. Within a few minutes, he raised his head with surprise and asked seriously: "You said that TAAS crystal is the Weyl semimetal material predicted more than 80 years ago?"

"right!"

"It's basically true." Xu Mang nodded: "If there are no problems with my calculations, I just need to prepare high-quality TAAS crystals and then use my modified STM equipment for high-precision measurements, and it will be fine!"

Liu Guofang said seriously: "I will arrange it right away!"

Leave the Materials Department building,

Xu Mang's heart returned to peace, and Director Liu Guofang promised to complete the preparation of high-quality TAAS crystals as soon as possible. The estimated time is about three days.

three days

That’s almost it!

Xu Mang calculated the announcement time for the June meeting. It will be released almost a week later. It is a unilateral resolution by the United States and a resolution to launch the so-called Global Condensed Matter Alliance. China is the only country missing from this organization.

Just thinking about it makes me angry!

A broken organization makes it look like the real thing.

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, a fire burned in his heart.
To be continued...