95后博士曹原獲選Nature年度十大科學(xué)人物

Yuan Cao’s teenage years were hardly typical. By age 18, he had already graduated from high school, completed an undergraduate degree at the University of Science and Technology of China in Hefei, and travelled to the United States to begin his PhD. He hasn’t slowed down since: this year, aged just 21, Cao had two papers published on strange behaviour in atom-thick layers of carbon that have spurred a new field of physics. Cao admits that his situation is unusual, but says he isn’t special. After all, he did spend a full four years at university: “I just skipped some of the boring stuff in middle school.”

曹原年少時(shí)便令許多人望塵莫及。在18歲時(shí)，他已高中畢業(yè)，并在合肥中國(guó)科學(xué)技術(shù)大學(xué)完成本科學(xué)位，隨后前往美國(guó)攻讀博士學(xué)位。他也沒有停下前進(jìn)的腳步: 今年，年僅21歲的曹原發(fā)表了兩篇關(guān)于原子厚度的碳層中奇怪行為的論文，這開創(chuàng)了物理學(xué)的一個(gè)全新領(lǐng)域。曹原承認(rèn)自己的情況并不常見，但是并不特別。最后，他稱自己和普通人一樣也上了四年大學(xué)，只是在中學(xué)時(shí)期跳過了一些無聊的東西。

Pablo Jarillo-Herrero’s group at the Massachusetts Institute of Technology (MIT) in Cambridge was already layering and rotating sheets of carbon at different angles when Cao joined the lab in 2014. Cao’s job was to investigate what happened in two-layer stacks when one graphene sheet was twisted only slightly with respect to the other, which one theory predicted would radically change the material’s behaviour.

曹原2014年加入麻省理工學(xué)院(MIT)Pablo Jarillo-Herrero團(tuán)隊(duì)時(shí)，該團(tuán)隊(duì)已經(jīng)在從不同角度對(duì)碳片進(jìn)行分層和疊加研究。曹原的工作是研究當(dāng)一個(gè)石墨烯薄片相對(duì)于另一個(gè)稍微扭曲時(shí)，兩層疊加層中會(huì)發(fā)生什么，一種理論預(yù)測(cè)這將從根本上改變這種材料的性質(zhì)。

Many physicists were sceptical about the idea. But when Cao set out to create the subtly twisted stacks, he spotted something strange. Exposed to a small electric field and cooled to 1.7 degrees above absolute zero, the graphene — which ordinarily conducts electricity — became an insulator (Y. Cao et al. Nature 556, 80–84; 2018). That by itself was surprising. “We knew already that it would have a big impact on the community,” says Cao. But the best was yet to come: with a slight tweak to the field, the twisted sheets became a superconductor, in which electricity flowed without resistance (Y. Cao et al. Nature 556, 43–50; 2018). Seeing the effect in a second sample convinced the team that it was real.

許多物理學(xué)家對(duì)此有些懷疑。當(dāng)曹原開始制作這些巧妙扭曲的結(jié)構(gòu)時(shí)，他發(fā)現(xiàn)了一些奇怪的東西。如果把石墨烯暴露在一個(gè)小電場(chǎng)中，冷卻到絕對(duì)零度以上1.7度，通常導(dǎo)電的石墨烯就變成了絕緣體(2018年《自然》第556期，80-84頁，曹原等人) 。這個(gè)發(fā)現(xiàn)已經(jīng)非常令人震驚了。曹原說，我們知道這將對(duì)科學(xué)界產(chǎn)生巨大影響，但是遠(yuǎn)遠(yuǎn)不止于此。曹原發(fā)現(xiàn)，只要對(duì)電場(chǎng)稍加調(diào)整，扭曲的薄片就會(huì)變成超導(dǎo)體，超導(dǎo)體里的電流就可以毫無阻礙地流動(dòng)(2018年《自然》第556期，43-50頁，曹原等人)。他的團(tuán)隊(duì)從第二個(gè)樣本中也得到了同樣的結(jié)果，并確認(rèn)曹原的想法是正確的。

Cao, now 22, doesn’t yet know where he’d like his career to lead. “On magic-angle graphene, we still have a lot of things to do,” he says. But universities around the world are already eyeing him for not only postdoctorate jobs, but also faculty positions, says physicist Changgan Zeng, Cao’s undergraduate supervisor and mentor at the University of Science and Technology of China. “Among condensed-matter physicists in China, everybody knows his name,” Zeng says. The university would gladly have him back, but Zeng expects that Cao will stay in the United States for now. “There, it’s easier to see the stars.”

未來的科研生涯將會(huì)走向何方，現(xiàn)在22歲的曹原說自己并不知道。他說：“對(duì)于石墨烯的‘魔角’，我們要做的事情還有很多。”他的本科導(dǎo)師，中國(guó)科學(xué)技術(shù)大學(xué)物理學(xué)家曾長(zhǎng)淦表示，世界各地已經(jīng)有多所大學(xué)向他拋出了橄欖枝，不僅有博士后的職位，而且還有教職崗位。“在中國(guó)的凝聚態(tài)物理學(xué)家中，每個(gè)人都知道他的名字。”曾長(zhǎng)淦說。他回來的話中科大會(huì)很高興，但曾長(zhǎng)淦希望曹原現(xiàn)階段留在美國(guó)。“那里，更容易取得更大的成就。”