Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Graphene becomes superconductive - Electrons with "no mass" flow with "no resistance"


A joint research team in Japan has developed a method to grow high-quality graphene on a silicon carbide (SiC) crystal by controlling the number of graphene sheets.

Graphene is a single-atomic carbon sheet with a hexagonal honeycomb network (Fig. 1). Electrons in graphene take a special electronic state called Dirac-cone where they behave as if they have no mass. This allows them to flow at very high speed, giving graphene a very high level of electrical conductivity.

Figure 1: Crystal structure of Ca-intercalated bilayer graphene fabricated on SiC substrate. Insertion of Ca atoms between two graphene layers causes the superconductivity.

Copyright : Tohoku University

Figure 2: Temperature dependence of electrical resistivity of Ca-intercalated bilayer graphene, measured by the micro four-point-probe method (inset). The resistivity shows a rapid decrease at around 4 K and reaches "zero" at 2 K, showing the emergence of superconductivity.

Copyright : Tohoku University

This is significant because electrons with no mass flowing with no resistance in graphene could lead to the realization of an ultimately high-speed nano electronic device.

The collaborative team of Tohoku University and the University of Tokyo has developed a method to grow high-quality graphene on a silicon carbide (SiC) crystal by controlling the number of graphene sheets. The team fabricated bilayer graphene with this method and then inserted calcium (Ca) atoms between the two graphene layers like a sandwich (Fig. 1).

They measured the electrical conductivity with the micro four-point probe method and found that the electrical resistivity rapidly drops at around 4 K (-269 °C), indicative of an emergence of superconductivity (Fig. 2).

The team also found that neither genuine bilayer graphene nor lithium-intercalated bilayer graphene shows superconductivity, indicating that the superconductivity is driven by the electron transfer from Ca atoms to graphene sheets.

The success in fabricating superconducting graphene is expected to greatly impact both the basic and applied researches of graphene.

It is currently not clear what phenomenon takes place when the Dirac electrons with no mass become superconductive with no resistance. But based on the latest study results, further experimental and theoretical investigations would help to unravel the properties of superconducting graphene.

The superconducting transition temperature (Tc) observed in this study on Ca-intercalated bilayer graphene is still low (4 K). This prompts further studies into ways to increase Tc, for example, by replacing Ca with other metals and alloys, or changing the number of graphene sheets.

From the application point of view, the latest results pave the way for the further development of ultrahigh-speed superconducting nano devices such as a quantum computing device, which utilizes superconducting graphene in its integrated circuit.

Publication Details:

Authors: Satoru Ichinokura, Katsuaki Sugawara, Akari Takayama, Takashi Takahashi and Shuji Hasegawa
Title: Superconducting Calcium-Intercalated Bilayer Graphene
Journal: ACS Nano (2016)
DOI: 10.1021/acsnano.5b07848

Takashi Takahashi
Advanced Institute for Materials Research, Tohoku University
Tel: +81-22-217-4816
Fax: +81-22-217-4818

Associated links
Original article from Tohoku University

Ngaroma Riley | Research SEA

More articles from Materials Sciences:

nachricht Scientists have a new way to gauge the growth of nanowires
19.03.2018 | DOE/Argonne National Laboratory

nachricht Researchers demonstrate existence of new form of electronic matter
15.03.2018 | University of Illinois at Urbana-Champaign

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Physicists made crystal lattice from polaritons

20.03.2018 | Physics and Astronomy

Mars' oceans formed early, possibly aided by massive volcanic eruptions

20.03.2018 | Physics and Astronomy

Thawing permafrost produces more methane than expected

20.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>