Westlake News ACADEMICS

Xiao Lin's Team Published Paper on Nature Communications

Shan XU
01, 2020

PRESS INQUIRIES Yi FENG
Email: fengyi@westlake.edu.cn
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Beijing, July 31st, 2020 - In a recent paper named T-square resistivity without Umklapp scattering in dilute metallic Bi2O2Se published on Nature Communications, Principal Investigator Xiao Lin and his team at Westlake University raised new questions on the mechanism of quadratic temperature (T) dependent resistivity, urging academics to further investigate in the electron-electron (e-e) scattering in Fermi liquids. The paper also aims at further clarifying the e-e scattering of Bi2O2Se, an excellent optoelectronic material as well as potentially the next star semiconductor candidate with high-performance and low power consumption.


Figure: Crystal structure of Bi2O2Se

 

Collision between electrons of a metal leads to a T-square resistivity. Postulated in 1930s by Landau and Pomeranchuk and independently by Baber, this feature has been widely documented in elemental and strongly correlated metals. However, Lin contested in the paper that the Fermi liquids e-e scattering theory failed to explain the resistivity of Bi2O2Se.

 

This paper is the latest milestone of Lin's scientific odyssey. In 2015, he observed T2 resistivity in the diluted metal SrTiO3, which challenged existing theories, causing great controversy which continues to this day. To support his contention, Lin devoted his time to looking for new materials and finally found Bi2O2Se, which had a simpler mechanism than SrTiO3, which made the recent paper more convincing. 

 

Figure 2 shows the correlation between the coefficient A of the resistivity temperature squared of Bi2O2Se and SrTiO3 and the Fermi energy EF, and compared them with different Fermi liquids, and found no difference. This shows that the temperature behavior of resistivity is most likely to come from e-e scattering in Bi2O2Se and SrTiO3, and the specific mechanism is not yet clear.

 

Figure 2 The correlation between the temperature square coefficient A of the resistivity and the Fermi energy EF.

 

To a certain extend, this study introduced an element of surprise to theory researchers with its rigorous and detailed experiment data and calculations which challenged the existing e-e scattering mechanism. Lin believed that this was the job of an experimental researcher. Theory and practice have always been the two pillars in the progress of science. This paper helps experiment to take a small step forward, and the theory needs to catch up quickly; the next time it might be theory that leads and experiment will follow.

 

Bi2O2Se has huge potential in application such as field-effect transistor, integrated optoelectronic device, and infrared photodetector. Studying the e-e scattering mechanism of materials will help us further understand the process of carrier transport in materials, which is also very important for device development.

 

Coming up, Lin's research group will conduct in-depth study on the physical characteristics of Bi2O2Se from both basic research and application point of view. "The pedestal of science is built bricks by brick. I believe that we are doing meaningful work, so even if it is just a small brick that we are contributing, it is still satisfying,” said Lin.

 

The corresponding co-author of the paper Xiao Lin, special researcher at School of Physics, Westlake University, is joined by first author Jialu Wang, PhD candidate of year 2018 at Westlake University. Special researcher Shi Liu and Zhi Ren also contributed to the paper. 

 

To access the paper, please visit: https://www.nature.com/articles/s41467-020-17692-6