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Science AMA Series: The discovery of a new particle called Weyl challenged our understanding of quantum field theory and was one of the Physics World’s 2015 Breakthroughs of the year. Mazhar Ali is her
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My name is Mazhar Ali and I am a researcher with the Max PIank Institute for Microstructure Physics in Halle, Germany and also at IBM in San Jose, California. Before that I was at Princeton where many of us worked on and discovered some of the first Dirac and Weyl materials, including the first “type II” Weyl semimetal, WTe2, which was on the frontpage of r/science last week. Dirac and Weyl materials are a super hot topic in condensed matter physics right now, but has branched out and captured the attention of chemists, particle physicists, materials scientists, electrical engineers and more! These materials host massless dirac electrons (similar to graphene) and so can have “light-like” electrons moving at extremeley high mobilities! Recently, people have been able to use the intracies of the electronic structure of a material to massage these massless dirac electrons into becoming Weyl electrons; still massless, but with the added bonus of having spin up and spin down be energetically different! We will see in the near future what we can do with these new particles, but first we need to understand everything better. Out of the 3 camps of Fermions (Weyl, Dirac, and Majorana) we had previously only realized Dirac fermions in real life. Now we have realized the 2nd camp, Weyl! Majorana might be just around the corner too! It is a very exciting time to be involved! I am here to answer any questions you all might have about Dirac and Weyl materials, physics, chemistry, etc! Or, if you just want to know about solid state and materials chemistry, AMA! A few links to a few of the relevant papers (obviously there are loads more): Titanic Magnetoresistance in WTe2: http://www.nature.com/nature/journal/v514/n7521/full/nature13763.html Type II Weyl Semimetals: http://www.nature.com/nature/journal/v527/n7579/full/nature15768.html Cd3As2, a Dirac Semimetal: http://www.nature.com/nmat/journal/v13/n7/full/nmat3990.html Ultrahigh electron mobility in Cd3As2: http://www.nature.com/nmat/journal/v14/n3/full/nmat4143.html Type I Weyl Semimetal (open access): http://journals.aps.org/prx/abstract/10.1103/PhysRevX.5.031013 A very nice viewpoint on Weyl electrons by Leon Balents (professor at UCSB): http://physics.aps.org/articles/v4/36 open access, arXiv versions of most of the above articles can be found through google fairly easily as well. I will be back at 2 pm EST (11 am PST, 7 pm UTC) to answer your questions, ask me anything! EDIT: I am back! May go for lunch in about an hour, but then will be back again after! EDIT 2: Hey all! Gonna take a lunch break, be back in about an hour or so! (Currently 12:20 PST) EDIT 3: Back again!