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Research ARPES measurements of Calcium doped graphene. Left: the Fermi surface of graphene (top) and the Dirac cone (bottom). Right: The kink in the spectral function in the two crystallographic main directions. The scientists analysed the strength of the kink in order to estimate the superconducting critical temperature.
Image Credit: A. Grüneis and A.V. Fedorov

Published on February 13th, 2014 | by James Ayre

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Turning Graphene Into A Superconductor — Pairing Mechanism Unveiled



Graphene as a superconductor? That may soon be a reality, thanks to new research from the University of Vienna. Scientists there have found what appears to be an effective means of inducing super conductivity in the material — a potential superconducting coupling mechanism for the material.

The researchers utilized the ARPES method — a method of inquisition that uses light to investigate the electronic properties and interactions of a material — to determine that calcium is the most promising looking dopant-pairing for graphene.

ARPES measurements of Calcium doped graphene. Left: the Fermi surface of graphene (top) and the Dirac cone (bottom). Right: The kink in the spectral function in the two crystallographic main directions. The scientists analysed the strength of the kink in order to estimate the superconducting critical temperature. Image Credit: A. Grüneis and A.V. Fedorov

ARPES measurements of Calcium doped graphene. Left: the Fermi surface of graphene (top) and the Dirac cone (bottom). Right: The kink in the spectral function in the two crystallographic main directions. The scientists analysed the strength of the kink in order to estimate the superconducting critical temperature. Image Credit: A. Grüneis and A.V. Fedorov

The University of Vienna provides more:

Nikolay Verbitskiy and Alexander Grüneis from the University of Vienna together with Alexander Fedorov and Denis Vyalikh from IFW-Dresden and TU-Dresden and Danny Haberer from the University of California at Berkeley and their colleagues employed this technique — the so-called Angle-resolved photoemission spectroscopy (ARPES) — at the Elettra synchrotron in Trieste where they researched the interaction of a series of electron dopants (Cs, Rb, K, Na, Li, Ca) with monolayer graphene.

According to the findings of the scientists, calcium is the most promising candidate to induce superconductivity in graphene with a critical temperature of about 1.5K. This critical temperature is rather low compared to e.g. fullerenes which superconduct at 33K. However, graphene offers several huge advantages over many other materials. Since it consists only of carbon atoms arranged in single layers, it is easy to be chemically functionalized. Moreover, it can be grown in multiple numbers of atom layers in various stacking orders and can be doped in several different ways. Thereby, it gives a multitude of options to experiment with.

The researchers note that while graphene won’t set any records with regard to the temperatures at which superconducting can be achieved, it will help researchers gain a better understanding of the phenomenon in general — thanks to the ease with which the material can be modified.

The new research was just published in the journal Nature Communications.

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About the Author

James Ayre's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.



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