3D material that behaves like graphene discovered

June 5, 2014

Scientists at Oxford, SLAC, Stanford and Berkeley Lab have discovered that a sturdy 3D material, cadmium arsenide, mimics the electronic behavior of 2D graphene. This illustration depicts fast-moving, massless electrons inside the material. The discovery could lead to new and faster types of electronic devices. (Credit: Greg Stewart/SLAC)

Cadmium arsenide could yield practical devices with the same extraordinary electronic properties as 2D graphene, researchers from Oxford, SLAC, and Berkeley Lab have found.

In addition, the new “semimetal” material exists in a sturdy 3D form that should be much easier to shape into electronic devices such as very fast transistors, sensors and transparent electrodes, the researchers say.

The results are described in a paper published May 25 in Nature Materials.

There is a quest to find graphene-like materials that are three-dimensional, and thus much easier to craft into practical devices.

Two other international collaborations based at Princeton University and in Dresden, Germany, have also been pursuing cadmium arsenide as a possibility. One published a paper on its results in the May 7 issue of Nature Communications, and the other has posted an unpublished paper on the preprint server arXiv.

The research team also included scientists at Fudan University in Shanghai, the Chinese Academy of Sciences and Diamond Light Source. The work was partially funded by the U.S. Department of Energy Office of Science and the Defense Advanced Research Projects Agency (DARPA) Mesodynamic Architectures program.

Abstract of Nature Materials paper

Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals, axion insulators and topological superconductors), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd3As2, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO2 and Na3Bi, Cd3As2 is stable and has much higher Fermi velocities. Furthermore, by in situ doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.