Chapter 339 Searching for the Mechanism of High-Temperature Superconductivity
In the conference room, Xu Chuan took the notebook from Fan Pengyue and flipped through the data inside.
The researcher who figured out the ultra-low temperature superconducting copper-carbon-silver composite material is called ‘Song Wenbo’, a professor poached from Wuli University, whose main research field was material chemistry before.
This time, Professor Song was able to figure out the ultra-low temperature superconducting material, half by experience and half by luck.
He did not use the powder metallurgy method of traditional materials science, nor did he use the high temperature and high pressure synthesis method commonly used in the study of superconductor materials to study copper-carbon-silver composite superconducting materials, but took the development route of nanomaterial preparation and molecular modification.
He first prepared the copper-carbon-silver composite material by nano means, and then manipulated and adjusted the tiny atomic structure by vapor deposition.
Compared with the conventional powder metallurgy method for preparing copper-carbon-silver composite materials, this new method solves the problem of weak interface bonding between copper and carbon and a large number of holes in the composite material.
Compared with the high temperature and high pressure superconductor research method, it also avoids the disadvantages of poor wettability of copper atoms and carbon atoms even at high temperatures.
It has to be said that Wuli University, which ranks among the top five domestic universities in the field of materials research, is still quite capable.
A professor of materials chemistry who is above average and not top-notch, has sufficient experience and means to deal with the development of new materials.
If there is a disadvantage, it is that in the process of two-dimensional film deposition, a binder is used. Even if it is only a trace amount of binder, this will destroy the purity of the copper-carbon-silver composite material itself to a certain extent.
This not only means that it requires a lower temperature to make this thin film material reach the superconducting energy gap. It also means that the performance of the material itself is greatly reduced.
"It's interesting. Call Professor Song and ask if he has time now. If so, ask him to come over. I have some questions to consult him."
After reading the information in the computer, Xu Chuan raised his head with interest, tapped his fingers on the table lightly, and said to Fan Pengyue.
To be honest, the value of this ultra-low temperature superconducting copper-carbon-silver composite material itself is not that great.
First of all, the material studied by Professor Song is a two-dimensional film structure. It is still very difficult to process it into a superconducting material of wire or other shapes.
Secondly, superconductivity at a temperature of 43.5K (about -230 degrees Celsius) has actually been achieved outside for a long time.
For example, the Large Hadron Collider at CERN.
To accelerate particles, a super-strong magnetic field is required, and a strong magnetic field requires superconducting materials to reach the limit.
The LHC particle collider uses niobium-tin alloy. After being cooled by liquid helium, this material has achieved superconductivity in a normal pressure environment and can be mass-produced.
Apart from low-temperature superconductivity, high-temperature superconductivity has actually been studied for a long time.
As early as 1987, scientists from China, the United States, and small island countries discovered that "barium-yttrium-copper oxide" has Tc in the liquid nitrogen temperature zone, thus having superconductivity.
(Tc refers to the critical temperature, which is the temperature at which the material changes from the normal state to the superconducting state. For example, when the temperature of mercury is slightly lower than 4.2K, the resistance of mercury suddenly disappears, showing a superconducting state, so the Tc of mercury is 4.2K, about minus 268.95 degrees Celsius.)
But due to the fact that copper oxide superconductors are like very brittle ceramic materials, you can't pull them into thin wires, plus the high manufacturing cost, and the problem of failure due to the slightest impurity contamination, high-temperature superconductivity has not been applied to industry.
So the temperature superconductivity of 43.5K alone does not have much practical value.
Not only does it require liquid helium freezing to superconduct, it cannot be industrially produced.
However, he found some very interesting things in this material.
If you can figure it out, maybe you can explain the superconductivity of high-temperature superconducting materials from another perspective.
You have to know that the high-temperature superconductivity of superconducting materials has not been truly explained in the future, let alone in the early 2020, even in a dozen years.
Even if he developed room-temperature superconducting materials in the future, he could not explain the reason for the existence of room-temperature and high-temperature superconductors.
If it were in other fields, this would be almost impossible or extremely difficult.
How could practical results be achieved without a theory?
But in the field of materials science, it is common for experiments to produce results by chance without a theory.
Many materials used in society today actually have results first, and then the results are studied to obtain theories.
If the superconductivity of high-temperature and ultra-temperature superconducting materials can be explained clearly, it will definitely be a huge improvement for the development of superconducting materials.
Fan Pengyue nodded, took out his mobile phone from his pocket and made a call. After asking, he hung up the phone.
Not long after, there was a knock on the door outside the conference room.
Xu Chuan said, "Come in."
Then, the door opened and a middle-aged man with gold-rimmed glasses walked in.
"Mr. Fan, are you looking for me?"
Song Wenbo walked in and asked, but his eyes fell on Xu Chuan who was sitting at the desk.
The familiar figure made him pause for a moment, and he asked half doubtfully, "Are you Academician Xu?"
When the Chuanhai Materials Research Institute recruited him, he knew that the real owner behind this laboratory was the famous Professor Xu Chuanxu.
He recognized Xu Chuan, but he was a little skeptical.
Because from the time he joined the company until now, most people in the Chuanhai Materials Research Institute had never seen the real boss, let alone him.
So even if they saw the real person, they were a little skeptical about whether they had seen it wrong.
On the opposite side, Fan Pengyue looked at Xu Chuan and said with a smile: "Look at you, you have been a hands-off boss for so long that the company employees don't recognize you anymore."
Xu Chuan ignored Fan Pengyue. He smiled at Song Bai and said, "It's me. Professor Song, please sit down. I asked you to come here this time mainly because I want to consult you on some issues."
Song Wenbai walked over quickly and asked nervously, "You say."
Although he is much older than the one in front of him, there is a huge difference between the two in terms of knowledge and status.
There are only four academician-level giants in the entire Wuli University. Although he has seen and communicated with them, it is the first time that such an academician giant has become his immediate superior.
Moreover, this is in a private enterprise, not in a school. The power of the leader over the subordinates is greater, and the pressure on him to come is also greater.
Of course, if you seize the opportunity, especially for the Sichuan Hai Materials Research Institute, which has just begun to expand, the future will be very bright.
He is almost fifty years old this year, and his academic level is there. Although it is not weak, it is not top-notch, so his prospects for promotion in Wuli are almost at the top.
And changing to a new environment may allow him to go further. This is also the reason why he was poached, not only for money, but also for the hope of promotion.
Xu Chuan didn't care too much about these things. He connected the computer on his desk to the virtual projection and opened the research data of ultra-low temperature superconducting copper-carbon-silver composite materials.
"I have some questions about the ultra-low temperature superconducting copper-carbon-silver composite material you have developed."
"First, about the x-ray diffraction analysis data. Through x-ray research, the sample has a structural phase transition process from orthorhombic to tetragonal when x≈0.04, and the unit cell volume increases with the increase of copper content."
"And the zero resistance temperature measured by the R-T curve will drop rapidly with the increase of copper content until it drops below 50K. The zero resistance temperature decreases with the increase of X, and there is no mutation at the structural phase transition point."
"What do you think about this?"
There is no analytical answer to this question in the data given to him by Fan Pengyue, which means that the analysis results have not been made yet.
If you want to know, it is fastest to ask the person in charge of the experiment directly.
Song Wenbo thought for a while and said, "According to my speculation, this should be the effect of doping with elements such as adhesives on copper-carbon-silver composite materials. The electron doping of adhesives will cause its lattice coefficient to change."
"When I was at Wuli University, I studied the effect of hole doping on electronic structure. Under external pressure, the magnetism is gradually suppressed by the many-body effect of strongly correlated system electrons."
"This may be the reason why the zero resistance temperature decreases with the increase of X after the temperature drops below 50K, and there is no sudden change at the structural phase transition point."
Listening to Song Wenbo's explanation, Xu Chuan tapped his fingers on the table, and his mind fell into deep thought.
The effect of hole doping on electronic structure and lattice coefficient?
If he remembered correctly, when he was studying copper-carbon-silver composite superconducting materials in his previous life, he did not study copper-carbon-silver composite materials at the beginning, but oxidized copper-silver nanomaterials.
Because oxidized materials are recognized as the most promising to break through the high-temperature superconducting limit.
The reason why he replaced oxygen with carbon later was actually caused by an accidental experimental accident.
The reason why oxide superconductors have become mainstream is not only because they can break the limitations of ultra-low temperature superconductivity, but also because copper oxide high temperature superconductors also show many strange properties.
For example, its superconducting phase has d-wave pairing symmetry, which is different from the s-wave symmetry of conventional superconductors;
Another example is that its parent material has an antiferromagnetic Mott insulating phase, and there are pseudo gaps and Fermi arcs in the underdoped region.
Today, Song Wenbo's words brought him a new inspiration, and the key that he had not figured out before might be answered.
If the original copper-silver oxide nanomaterial is regarded as a superconductor, perhaps the carbon accidentally doped into the original material may be the key to breaking the Tc critical temperature.
Perhaps, he can find the superconducting formation mechanism of copper oxide high temperature superconductors.
If successful, this will definitely be the biggest breakthrough in the history of high temperature superconducting materials!
And with this theory, he can naturally develop superconducting materials at the fastest speed.
But now he needs more data and information to verify his ideas!
PS: Make up for yesterday's second chapter, ask for monthly tickets