Scientists Discover Chiral Crystals Exhibiting Exotic Quantum Effects
March 21, 2019 | Princeton UniversityEstimated reading time: 5 minutes
They studied the atoms’ arrangement on the surface of the material using several techniques, such as checking for the right kind of symmetry using the scanning tunneling microscope in Hasan’s Laboratory for Topological Quantum Matter and Advanced Spectroscopy located in the basement of Princeton’s Jadwin Hall.
The chiral crystals were then taken to Lawrence Berkeley National Laboratory, where members of the research team used high energy X-rays to knock electrons off the surface, as analyzing the patterns made by the emitted electrons can reveal their masses and velocities. The researchers found that electrons emitted from deeper within the samples had effectively zero mass, and their velocity and spin distributions revealed both their chiral (handed) behavior and their collective monopole-like character.
“It is amazing to see that somehow the chirality of the crystal structure has a profound effect on the electrons in these materials — they are now massless and chiral,” said Tyler Cochran, a physics graduate student and one of the three co-first authors of the paper.
“We expect this is the tip of the iceberg,” said fellow graduate student and co-first author Ilya Belopolski. “There are so many chiral crystals in nature. It would be great to check how many of those are topological. This would be a fantastic playground for new types of quantum phenomena.”
“Chiral crystals seem to be a perfect source for novel electronic phases of matter and more excitingly, for the massless electrons of the kind physicists were searching for many years,” said Daniel Sanchez, another co-first author. “This is just terrific that we found them.”
The researchers were excited to discover this quantum-level chiral behavior of electrons, said Guoqing Chang, a postdoctoral research associate in Hasan’s lab who was the first author of the theory paper predicting these topological phenomena. “It is one of those examples where our theoretical predictions have been realized experimentally,” he said. “That does not always happen. We predicted something new that agreed with what Mother Nature had in store for us — this is just exciting.”
“It is indeed immensely satisfying when you predict something exotic and it also appears in the laboratory experiments,” Hasan said. “This is not the first time we have succeeded in predicting topological effects in quantum physics. We successfully predicted some of the new bismuth-based topological insulators that are now among the mostly studied compounds in the field.”
He added, “We are combining theory and experiments to advance the knowledge frontier.”
The team included numerous researchers from Princeton’s Department of Physics, including present and past graduate students Daniel Sanchez, Ilya Belopolski, Tyler Cochran, Nasser Alidoust, Daniel Multer, Songtian Sonia Zhang, Nana Shumiya and Suyang Xu, and present and past postdoctoral research associates Jia-Xin Yin, Guoqing Chang and Weiwei Xie. Other co-authors were Xitong Xu, Kaustuv Manna, Vicky Süß, Cheng-Yi Huang, Xirui Wang, Guang-Qiang Wang, Tay-Rong Chang, Claudia Felser, Shuang Jia and Hsin Lin.
Page 2 of 2Suggested Items
DRAM Contract Prices for Q2 Adjusted to a 13–18% Increase
05/07/2024 | TrendForceTrendForce’s latest forecasts reveal contract prices for DRAM in the second quarter are expected to increase by 13–18%, while NAND Flash contract prices have been adjusted to a 15–20% Only eMMC/UFS will be seeing a smaller price increase of about 10%.
Happy’s Tech Talk #28: The Power Mesh Architecture for PCBs
05/07/2024 | Happy Holden -- Column: Happy’s Tech TalkA significant decrease in HDI substrate production cost can be achieved by reducing the number of substrate layers from conventional through-hole multilayers and microvia multilayers of eight, 10, 12 (and more), down to four. Besides reducing direct processing steps, yield will increase as defect producing operations are eliminated.
It’s Only Common Sense: Would You Join Your Own Company?
05/06/2024 | Dan Beaulieu -- Column: It's Only Common SenseIn the past few years, I have heard many company runners complaining about their workforce. They tell me that the government is paying people too much money not to work, too many young people are not interested in working every day, and there is just not the work ethic there once was when they were young.
The Knowledge Base: A CM’s Perspective on Box Build Practices
04/30/2024 | Mike Konrad -- Column: The Knowledge BaseIn the ever-evolving landscape of electronics manufacturing, the box-build process stands out as a critical phase that bridges the gap between individual component manufacturing and the delivery of a fully functional electronic system. This intricate procedure, encompassing the assembly of everything from PCBs to wire harnesses and mechanical enclosures, demands a high level of precision, efficiency, and innovation. As the electronics assembly industry expands and diversifies, understanding the best practices within box-build assembly has become paramount for manufacturers aiming to stay ahead in a competitive market.
North American PCB Industry Sales Down 23.8% in March
04/29/2024 | IPCIPC announced the March 2024 findings from its North American Printed Circuit Board (PCB) Statistical Program. The book-to-bill ratio stands at 1.13.