Latest research findings on LK99 from the Physics Department of Southeast University
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Hello everyone.
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I am Sun Yueyue from the Department of Physics at Southeast University.
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Today I will report to you on the latest research results of our group on LK99.
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Recently, the topic of extraterrestrial superconductivity has been very hot.
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We have seen many reports on this.
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As researchers in the field of superconductivity, we are very happy.
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We have received a lot of interest in our work.
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However, we have also noticed that some media or self-media outlets have been over-reporting or distorting our experimental results.
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Therefore, I would like to take this opportunity to introduce our findings to you through this video.
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Our work has already been published in the journal Accounts, so you will soon be able to read the full article.
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First of all, let me clarify the most important point.
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We have neither confirmed nor discovered extraterrestrial superconductivity.
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However, we have successfully observed zero resistance below 110K.
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This could be an important piece of evidence for the existence of superconductivity in this material.
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Now, let's take a look at the paper and provide you with a detailed explanation.
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Let me first introduce our research team at the School of Physics, Southeast University.
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This work was mainly carried out by three students: Hou Qiang, Wei Wei, and Zhou Xing.
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Professor Shi Yang and I also contributed to this work.
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Now, let's directly examine the figures in our paper and explain them to you.
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The first figure shows our X-ray diffraction results.
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On the left are the XRD results of two precursor materials.
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On the right are the XRD results of the materials we synthesized.
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We conducted X-ray diffraction on four batches of samples.
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We compared our X-ray results with those reported by a team from South Korea.
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The X-ray patterns of our samples match very well with the reported ones.
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In fact, our samples are even purer than theirs.
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The peak corresponding to impurities in their samples is much smaller in ours.
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Therefore, we can say that our samples have a higher level of purity.
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Now, let's move on to the most important part - the zero resistance results.
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Let's take a closer look at our measurements.
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We started measuring from 300K and gradually decreased the temperature.
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The current passing through the sample was one milliampere.
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Due to the fragility of the sample, it was difficult to shape it into a regular form.
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Therefore, we used an irregularly shaped sample to save time.
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We measured the resistivity using the four-probe method.
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Under a current of one milliampere, we observed that the resistivity exhibited slight semiconductor behavior at high temperatures.
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As the temperature decreased, the resistivity decreased as well.
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The most crucial observation was made at 110K.
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At this temperature, we observed that the resistance approached zero.
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Why do we say it approached zero?
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If you look at the scale of the resistance on this side, it is around 10^-5 to 10^-6 ohms.
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Considering the current of one milliampere, the corresponding voltage is around 10^-8 or 10^-9 volts.
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This is within the measurement range of our instrument, PBMS.
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Therefore, we believe that we have observed zero resistance.
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This is our sample.
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In our previous experiments, we observed a strange drop in resistance at around 250K.
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The cause of this drop is still unknown.
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It may be due to some impurities or other factors in the measurement setup.
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We are still investigating this phenomenon.
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We also conducted measurements of the superconducting transition under a magnetic field.
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We observed that the superconducting transition remained relatively stable under the applied magnetic field.
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The critical temperature, TC0, showed only a slight variation.
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However, there were some peculiarities in the superconducting transition under different magnetic fields.
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For example, at low fields such as 0 Tesla and 135 Tesla, the superconducting transition shifted to lower temperatures as the magnetic field increased.
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However, at 9 Tesla and 7 Tesla, the superconducting transition seemed to revert back.
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The reason for this behavior is still unknown.
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Finally, I would like to mention that we first observed a sharp drop in resistivity similar to a superconducting transition on the afternoon of August 1st.
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However, at that time, the resistivity did not reach zero and had a small value.
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Therefore, we intensified our sample selection process.
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We tested a total of six samples, but we only observed zero resistance in one of them.
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In most of the other samples, we observed behavior characteristic of semiconductors.
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In addition, we performed measurements of the Meissner effect on the sample with zero resistance.
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However, we did not observe complete diamagnetism in the magnetic measurements.
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Therefore, we speculate that if the zero resistance in our sample is caused by superconductivity, its superconducting component is relatively low.
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This concludes the main findings of our work.
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I would like to express my sincere gratitude to the three students who worked diligently on this project.
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I would also like to reiterate the most important points.
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We have successfully observed zero resistance below 110K in the LK99 material.
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However, this does not constitute evidence of room temperature superconductivity.
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Further exploration and measurements are needed to determine if room temperature superconductivity exists.
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Our team will continue to make efforts in this direction.
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We hope to bring you better results in the future.
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Thank you, everyone.
Sun Yuyue, a member of the research team, discusses the team's latest research on extraterrestrial super islands and addresses media misinterpretations.
This video in Chinese was translated to Čeština, English, Español, Français, Polski, 中文 on August 02, 2023, using Targum.video AI translation service.
