12 Mar 2019
Researchers have developed a method to produce super-thin quantum materials with extraordinary electronic behaviour from semiconductors.
Scientists from the Department of Energy’s Lawrence Berkeley National Laboratory, California, US, have designed a method in which semiconducting materials have been turned into quantum machines. This work could revolutionise the field, and lead to new efficient electronic systems and exciting physics.
Quantum machines are generally made from two-dimensional (2D) materials, often graphene. These materials are one atom thick and can be stacked. When the materials form a repeating pattern, this can generate unique properties.
Studies with graphene have resulted in large advancements in the field of 2D materials. A new study has found a way to use two semiconducting materials – tungsten disulphide and tungsten diselenide – to develop a material with highly interacting electrons. The researchers determined that the ‘twist angle’ – the angle between the two layers – provides the key to turning a 2D system into a quantum material.
‘This is an amazing discovery because we didn't think of these semiconducting materials as strongly interacting,’ said Feng Wang, Professor of Physics at UC Berkeley. ‘Now this work has brought these seemingly ordinary semiconductors into the quantum materials space.’
The tungsten disulfie and tungsten diselenide samples were fabricated using a polymer-based technique to build stacks from flakes approximately tens of microns in diameter. A transmission electron microscope (TEM) was then used to take atomic-resolution images of the device and see how the lattices lined up.
Future work will look at applications of the system in optoelectronics and miniature electronic systems, which would allow electrons to flow in devices with very low resistance.