Researchers from Berkeley Lab have discovered a “3D” material which shares the electrical properties of graphene, which could be used to create faster transistors and more compact hard drives.


Graphene, the strongest material in the world, is a fascinating material not only for its strength, but for its structure, and other physical properties. Electrons can travel through graphene many times faster than they can through silicon, the semiconductor used to create computer chips, circuit boards, and other electronic components.

Existing as a single atomically thin sheet of carbon atoms connected in a distinctive “honeycomb lattice” shape, graphene is considered a two-dimensional (planar) material.

The crystal lattice structure of graphene

The crystal lattice structure of graphene

In a study led by Yulin Chen, a physicist from Oxford University, a collaboration of researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) discovered that sodium bismuthate can exist in a state that shares many of the same properties as graphene. However, in this case the material exists as a three-dimensional topological insulator, known as a “three-dimensional topological Dirac semi-metal” – or “3DTDS”.

“A 3DTDS system could provide a significant improvement in efficiency in many applications over graphene because of its 3D volume,” Chen says. “Also, preparing large-size atomically thin single domain graphene films is still a challenge. It could be easier to fabricate graphene-type devices for a wider range of applications from 3DTDS systems.”


Oxford physicist Yulin Chen

According to Chen, a 3DTDS will conduct electrons even more efficiently than graphene will. Furthermore, as a topological insulator, 3DTDS possesses the unique property of functioning as a conductor and insulator simultaneously, with bulk electrons behaving like those in an insulator, and surface electrons behaving like those in graphene.

Besides providing a slew of fascinating implications to physicists, Chen’s research could someday lead to a number of technological advances which could affect consumer electronics. “Because of its 3D Dirac fermions in the bulk,” explained Chen, “a 3DTDS also features intriguing non-saturating linear magnetoresistance that can be orders of magnitude higher than the materials now used in hard drives, and it opens the door to more efficient optical sensors.”

Source: Berkeley Lab


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