创新背景

康斯坦丁·诺沃肖洛夫(Konstantin Novoselov)和安德烈·海姆(Andre Geim)首次创造了仅由一层碳原子组成的二维晶体。这种被称为石墨烯的材料从那时起就有了极大的发展。由于其特殊的强度，石墨烯如今被用于加固诸如网球拍、汽车轮胎或飞机机翼等产品。对于基础研究来说，物理学家不断在石墨烯材料中发现其他材料中没有观察到的新现象。

创新过程

双层石墨烯晶体，其中两个原子层相对于彼此轻微旋转，这对研究人员来说是有趣味的。大约一年前，研究团队证明，扭曲的石墨烯可以用来制造约瑟夫森结，这是超导器件的基本组成部分。

基于这项工作，研究人员现在能够用扭曲的石墨烯制作出第一个超导量子干涉装置(SQUID)，用于演示超导准粒子的干涉。传统的SQUID已经被用于医学、地质学和考古学等领域。它们灵敏的传感器能够测量磁场中哪怕是最小的变化。然而，SQUIDs只能与超导材料协同工作，因此在工作时需要用液氦或液氮冷却。

在量子技术中，SQUID可以承载量子比特(qubits)；也就是说，作为进行量子运算的元素。SQUID之于超导，就像晶体管之于半导体技术，是更复杂电路的基本构件。

博士生Elías Portolés发明的石墨烯SQUID并不比传统的铝制SQUID更灵敏，而且必须冷却到绝对零度以上2度以下的温度。然而，它确实大大拓宽了石墨烯的应用范围。五年前，研究人员已经能够证明石墨烯可以用来制造单电子晶体管。现在又增加了超导性。

值得注意的是，石墨烯的行为可以通过电极的偏压以有针对性的方式控制。根据所施加电压的不同，这种材料可以是绝缘的、导电的或超导的。研究人员可以利用固态物理提供的丰富光谱。

同样，半导体（晶体管）和超导体(SQUID)的两种基本组成部分现在可以组合在一种材料中。这使得构建新的控制操作成为可能。通常情况下，晶体管由硅制成，而SQUID由铝制成，不同的材料需要不同的加工技术。

麻省理工学院的一个研究小组发现了石墨烯的超导性，但全世界只有十几个实验小组在研究这一现象。更少的人能够将超导石墨烯转化为功能元件。

挑战在于，科学家们必须一个接一个地完成几个精细的工作步骤:首先，他们必须使石墨烯薄片彼此之间的相对角度精确地对齐。接下来的步骤包括连接电极和蚀刻孔。如果石墨烯被加热，就像在洁净室处理过程中经常发生的那样，两层重新排列，扭曲角就消失了。

创新关键点

研究人员制作出第一个超导量子干涉装置(SQUID)，用于演示超导准粒子的干涉。

创新价值

新研究将为超导研究带来新的可能性。有了这些成分，研究人员也许能更好地理解石墨烯的超导性最初是如何产生的。

Innovative development of quantum coherent and magnetic field sensitive superconducting components

A double-layer graphene crystal, in which two atomic layers rotate slightly relative to each other, is of interest to researchers. About a year ago, the research team demonstrated that twisted graphene could be used to create Josephson junctions, a basic building block of superconducting devices.

Based on this work, the researchers are now able to make the first superconducting quantum interference device (SQUID) out of twisted graphene, used to demonstrate the interference of superconducting quasi particles. Traditional squids have been used in fields such as medicine, geology and archaeology. Their sensitive sensors can measure even the smallest changes in the magnetic field. SQUIDs, however, can only work in conjunction with superconducting materials, so they need to be cooled with liquid helium or nitrogen as they work.

In quantum technology, squids can hold quantum bits (qubits); That is, as an element of quantum computation. Squids are to superconductivity what transistors are to semiconductor technology, the building blocks of more complex circuits.

PhD student Elias Portoles' graphene SQUID is no more sensitive than conventional aluminium squids and must be cooled to temperatures below two degrees above absolute zero. It does, however, greatly broaden the range of applications for graphene. Five years ago, researchers were able to show that graphene could be used to make single-electron transistors. And now superconductivity.

Remarkably, the behavior of graphene can be controlled in targeted ways by the bias of the electrodes. Depending on the voltage applied, the material may be insulating, conducting, or superconducting. Researchers can take advantage of the rich spectrum provided by solid-state physics.

Similarly, the two basic building blocks of a semiconductor (transistor) and a superconductor (SQUID) can now be combined in a single material. This makes it possible to build new control operations. Typically, transistors are made of silicon, whereas squids are made of aluminum, and different materials require different processing techniques.

Graphene's superconductivity was discovered by a team at the Massachusetts Institute of Technology, but only a dozen experimental groups around the world are studying the phenomenon. Even fewer people will be able to turn superconducting graphene into functional components.

The challenge was that the scientists had to perform several delicate working steps, one by one: First, they had to align the relative angles of the graphene sheets against each other precisely. The next steps involve connecting electrodes and etching holes. If the graphene is heated, as often happens during cleanroom treatments, the two layers rearrange and the twist Angle disappears.