An international research team led by the University of Göttingen has discovered new quantum effects in high-precision studies of natural two-layer graphene and has been interpreting them together with the University of Texas at Dallas using their theoretical work. This study provides new insight into the interaction of charge carriers and different phases and contributes to the understanding of the processes involved. The LMU in Munich and the National Institute for Materials Science in Tsukuba, Japan also participated in the research. [1]

Figure 1. Unexpected quantum effects in natural double-layer graphene

Figure 1 shows Among other unusual properties, graphene is known for its extremely high electrical conductivity. If the two individual layers of graphene are rotated at a very specific angle to each other, the system becomes superconducting, i.e. conducts electricity without any resistance, and exhibits other exciting quantum effects such as magnetism. However, the production of such a twisted graphene double-layer requires a higher technical effort.

This novel study used a naturally occurring form of double-layer graphene, where complex fabrication is not required. In a first step, the sample is isolated from a piece of graphite in the laboratory using a simple adhesive tape. [2] To observe quantum mechanical effects, the Göttingen team then applied a high electric field perpendicular to the sample: the electronic structure of the system changes and a strong accumulation of charge carriers with similar energy occurs.

At temperatures just above absolute zero of minus 273.15 degrees Celsius, the electrons in the graphene can interact with each other—and a variety of complex quantum phases emerge completely unexpectedly. For example, the interactions cause the spins of the electrons to align, making the material magnetic without any further external influence. [3]

"Future research can now focus on investigating further quantum states," say Professor Thomas Weitz and PhD student Anna Seiler, Faculty of Physics at Göttingen University. "In order to access other applications, for example novel computer systems such as quantum computers, researchers would need to find how these results could be achieved at higher temperatures. However, a major advantage of the current system developed in our new research lies in the simplicity of the fabrication of the materials." [4]

References:

1. https://journalbreak.com/unexpected-quantum-effects-in-natural-double-layer-graphene-sciencedaily/
2. https://newsfounded.com/ireland/unexpected-quantum-effect-in-natural-double-layer-graphene-sciencedaily/
3. https://www.labmanager.com/news/unexpected-quantum-effects-in-natural-double-layer-graphene-28636
4. https://www.sciencedaily.com/releases/2022/08/220815105554.htm

Cite this article:

Thanusri swetha J (2022), Unexpected quantum effects in natural double-layer graphene, Anatechmaz, pp.75