中文
HOME
HOME / LATEST NEWS / Content

High School Physics Department: Science Fair Lecture Series—Superconductivity in Quantum Materials

November 21, 2022

On November 16, 2022, the Science and Technology Guidance Office of Shanghai High School International Division invited Professor Qian Dong, Distinguished Professor and Vice Dean of the School of Physics and Astronomy of Shanghai Jiao Tong University, to give a lecture entitled "Superconductivity in Quantum Materials" to the students in Zhentao Building. As one of the lectures for the 2022 Science Fair entitled “Pursue · Excel”, this lecture attracted many students from grades 9-12 to come to listen and learn.

First, Prof. Qian started the lecture topic with momentum and energy in physics and described the stable structure and conductive properties of crystal materials in class. By observing the physical phenomenon of particle movements, three kinds of materials (gold, silver, and copper) at room temperature are listed to express their respective electrical conductivity and electron orbital distribution. This leads to the question of how the metallic atoms become electrically conductive in a sea of electrons. As we know, under the waves of electrons in a crystal material with a perfectly periodic structure, electrons have no resistance. Resistance occurs when the periodic structure loses its perfection. The loss of perfect periodicity in the crystal leads to resistance. Due to the widespread presence of impurities, various defects in the crystal, and in non-absolute zero temperature, atoms will also vibrate due to the movements that cause heat, resulting in electrical energy loss.

Then, how can we make a certain kind of material in a superconducting state with zero resistance so that it can transmit electrical energy with nearly zero loss? This is an important topic that scientists have been exploring since the superconductivity of mercury was discovered in 1911 by Prof. K. Onnes. Numerous experiments have been conducted to discover a new material that can show its superconductivity under certain high atmospheric pressure and low-temperature conditions ever since then.

However, the physical mechanism of superconducting materials has not been solved in academia so far, nor has it found superconductors with higher temperatures under conventional conditions. A recent study found that the highest superconducting temperature is 1.5 million times the atmospheric pressure as the superconducting temperature of LaH10 can reach up to 25 degrees below zero or so. During the lecture, students showed strong interest in superconducting materials and explored the research progress of material science and knowledge of physics with the professor in class.

Finally, Prof. Qian elaborated the application of superconducting materials, such as low-temperature superconducting cable, magnetic resonance imaging (MRI) used in hospitals, the usage of superconducting current limiters in the power supply system, and the application of superconducting technology in the precise measurement of weak magnetic fields, which includes the detection of mineral deposits, the detection of submarines, the internal magnetic field of the human body, cosmic rays, etc. In addition, future research of superconducting materials for computing areas has been prospected, such as the precise control of the phase of superconductors in quantum computing. After the lecture, the students had a lively discussion with expectations for the application of superconductors in future quantum computers. As one of the unique properties of quantum materials, the application of superconductivity has become a crucial part of the current development of science and technology.

The lecture by the experts in the frontiers of science is one of the platforms set up by SHSID for students to explore their interests. Through this lecture by Prof. Qian of SJTU, they can gain the development of frontier material science, which enlightens their curiosity for science. In the near future, we believe that they can go further and further in their pursuit of science and explore more interests on the way!

(Written by Tianzhou He, Yan Wang Pictures by Yan Wang Reviewed by Qian Zuo)