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Physicists snap first image of an ‘electron ice’
More than 90 years ago, physicist Eugene Wigner predicted that at low densities and cold temperatures, electrons that usually zip through materials would freeze into place, forming an electron ice, or what has been dubbed a Wigner crystal.
While physicists have obtained indirect evidence that Wigner crystals exist, no one has been able to snap a picture of one — until now.
UC Berkeley physicists published last week in the journal Nature an image of just such an electron ice sandwiched between two semiconductor layers. The image is proof positive that these crystals exist.
Graphene ‘camera’ captures real-time electrical activity of beating heart
Bay Area scientists have captured the real-time electrical activity of a beating heart, using a sheet of graphene to record an optical image — almost like a video camera — of the faint electric fields generated by the rhythmic firing of the heart’s muscle cells.
Graphene: A Talented 2D Material Gets a New Gig
A team of researchers led by Feng Wang, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a professor of physics at UC Berkeley, have tapped into their graphene system’s talent for juggling not just two properties, but three: superconducting, insulating, and a type of magnetism called ferromagnetism.
When Semiconductors Stick Together, Materials Go Quantum
A team of researchers led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a simple method that could turn ordinary semiconducting materials into quantum machines – superthin devices marked by extraordinary electronic behavior. Such an advancement could help to revolutionize a number of industries aiming for energy-efficient electronic systems – and provide a platform for exotic new physics.
New Pathway to Valleytronics
Feng Wang, a condensed matter physicist with Berkeley Lab’s Materials Sciences Division, led a study in which it was demonstrated that a well-established phenomenon known as the “optical Stark effect” can be used to selectively control photoexcited electrons/hole pairs – referred to as excitons –in different energy valleys.
Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors
A new argument has just been added to the growing case for graphene being bumped off its pedestal as the next big thing in the high-tech world by the two-dimensional semiconductors known as MX2 materials.
Using Carbon to Control the Light
Feng Wang is studying how electrical fields modulate the optical properties of a number of materials. The flip of a light switch – a nano-scale light switch – may some day dramatically boost the speed of data transmission, from streaming movies to accelerating the most data-intense computation.
Taking a new look at carbon nanotubes
Berkeley researchers develop technique for imaging individual carbon nanotube.
Five new Bakar Fellows pursue path to marketplace
Five UC Berkeley scientists eager to take their lab-bench discoveries into the marketplace have been awarded Bakar Fellowships to help them achieve their goals.
Graphene optical modulators could lead to ultrafast communications
UC Berkeley researchers have shown that graphene, a one-atom-thick layer of crystallized carbon, can be tuned electrically to modify the amount of photons absorbed. This ability to switch light on and off is the fundamental characteristic of a network modulator, opening the door to optical computing in handheld electronics.
Berkeley Lab Scientists Control Light Scattering in Graphene
Scientists at Berkeley Lab and UC Berkeley have learned to control the quantum pathways that determine how light scatters in graphene. As a sheet of carbon just a single atom thick, graphene’s extraordinary crystalline structure gives rise to unique electronic and optical properties. Controlling light scattering not only provides a new tool for studying graphene but points to practical applications for managing light and electronic states in graphene nanodevices.
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Please note: The views and opinions expressed in these articles are those of the authors and do not necessarily reflect the official policy or positions of UC Berkeley.
October 8, 2021
If the conditions are just right, some of the electrons inside a material will arrange themselves into a tidy honeycomb pattern like a solid within a solid. Physicists have now directly imaged these 'Wigner crystals', named after the Hungarian-born theorist Eugene Wigner, who first imagined them almost 90 years ago. Researchers had convincingly created Wigner crystals and measured their properties before, but this is the first time that anyone has actually taken a snapshot of the patterns, says study co-author Feng Wang, a physicist at the University of California, Berkeley. "If you say you have an electron crystal, show me the crystal," he says. For more on this story, please see our press release at Berkeley News
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