研究員のZHANG, Jiaqiさん（応用物理学領域、大島研究室）が国際会議The 9th International Symposium on Surface Science（ISSS-9）においてYoung Researchers' Awardを受賞しました。

　ISSSは、日本表面真空学会が主催で3年ごとに開催しています。同会議には国内外の表面科学・ナノサイエンス分野の研究者約500名が参加し、ハインリッヒ・ローラー賞（ハインリッヒ・ローラー博士‐1986年に走査型トンネル顕微鏡の設計でノーベル賞を受賞）の受賞式が行われることでも国際的に知られています。
　今回、ISSS-9は、令和3年11月28日から12月1日にかけてオンラインにて開催されました。

■受賞年月日
　令和3年12月1日

■研究題目、論文タイトル等
Mechanical properties of Pt atomic chains measured by TEM coupled with a quartz resonator

■研究者、著者
〇Jiaqi Zhang¹, Masahiko Tomitori¹, Toyoko Arai², Kenta Hongo¹, Ryo Maezono¹ and Yoshifumi Oshima¹
1) 本学
2) 金沢大学

■受賞対象となった研究の内容
Monatomic chains have shown unique physical and chemical properties, which draws a different picture from their bulk counterparts. It has been reported that the electrical or magnetic properties can be tuned by controlling the length of the atomic chains, which indicate that the mechanical properties is very important for their applications. However, the mechanical properties of atomic chains have not been clarified experimentally. To solve this problem, we developed an in-situ TEM holder equipped with a quartz resonator as force sensor to measure the mechanical properties of atomic chains when observing their atomic configurations.
A quartz length-extension resonator (LER) was used to measure the stiffness of platinum (Pt) monatomic chains from its frequency shift. Because the stiffness of the atomic chain suspended between the edge of LER and the fixed counter base can be measure precisely with very small oscillation amplitude (about 30 pm). The atomic resolution TEM images and videos were captured simultaneously with measuring the conductance and stiffness by our developed TEM holder.
The stiffness of atomic chains with 2-5 atoms were obtained. By subtracting the stiffness of the electrodes supporting the monatomic chain from the measured stiffness, we found that the stiffness of a Pt monatomic chain varied with the number of the constitute atoms in the chain. We investigated the stiffness of about 150 Pt monatomic chains for reproducibility and confirmed that the middle bond stiffness (25N/m) in the chain was slightly higher than that of the bond connect to the suspending tip (23N/m). In addition, the maximum elastic strain of individual bond in the chain was as large as 24%. These values were obviously different from the bulk counterpart. Such peculiar values could be briefly explained by the concept of "string tension".

■受賞にあたって一言
I'm incredibly honored with Young Researchers' Award in ISSS-9. First, I would express my appreciation to the organizer of this symposium for providing us the opportunity to share and discuss our researches. Importantly, I would describe my gratitude to Prof. Oshima, Prof. Tomitori, Prof. Arai, for their precious support. And I am also grateful to Oshima-LAB members for their kind encouragement. This award is an essential motivation for me to further research and contribute to nanoscience community.

令和4年1月12日