Category Physics

An illustration of refraction through a normal optical medium versus what it would look like for a medium capable of negative refraction. —Photo courtesy of Cory Dean

Engineers have directly observed for the first time negative refraction for electrons passing across a boundary between 2 regions in a conducting material. First predicted in 2007, this effect has been difficult to confirm experimentally. The electrons in the atomically thin material behave like light rays, which can be manipulated by such optical devices as lenses and prisms. The findings could lead to the development of new types of electron switches, based on principles of optics rather than electronics.

“The ability to manipulate electrons in a conducting material like light rays opens up entirely new ways of thinking a...

A top view of GrBP5 nanowires on a 2-D surface of graphene. Credit: Mehmet Sarikaya/Scientific Reports

A solution lies in bridging this gap where artificial meets biological – harnessing biological rules to exchange information between the biochemistry of our bodies and the chemistry of our devices. Engineers at the University of Washington unveil peptides that can provide just such a link. The team, led by UW professor Mehmet Sarikaya in the Departments of Materials Science & Engineering, shows how a genetically engineered peptide can assemble into nanowires atop 2D, solid surfaces that are just a single layer of atoms thick...

SEM – model of a metallic nano-network with periodic arrangement ( left) and visual representation of a fractal pattern (right). Credit: M. Giersig/HZB

HZB scientist Prof. Michael Giersig has recently demonstrated for these applications that networks of metallic mesh possessing fractal-like nano-features surpass other metallic networks in utility. These findings have now been published in the most recent edition of the journal Nature Communications.

Their new development is based on what is termed quasi-fractal nano-features. These structures have similarities to the hierarchical networks of veins in leaves. Giersig’s team was able to show that metallic networks with these features optimise performance of electrodes for several applications...

Highly nonlinear, fast and repeatable threshold switching behaviours of diffusive memristors.

A new type of nanodevice for computer microprocessors that can mimic the functioning of a neural synapse has been developed by Engineers at the University of Massachusetts Amherst. Such neuromorphic computing in which microprocessors are configured more like human brains is one of the most promising transformative computing technologies currently under study. Prof. Yang describes the research as part of collaborative work on a new type of memristive device.

Memristive devices are electrical resistance switches that can alter their resistance based on the history of applied voltage and current...