First semimetal hosting a single pair of collective electron quantum excitation fermions and no irrelevant electronic states

https://phys.org/news/2025-01-semimetallic-weyl-quantum-crystal.html

"topological semiconductor bismuth telluride adjusted creating (Cr,Bi)2Te3... large anomalous Hall effect ... zero energy gap at threshold between insulator/ metal... application: THz generation/ detection devices, since unlike semiconductors, semimetals have vanishing energy gap so they can absorb low frequency THz.. high-performance sensors, low-power electronics, optoelectronics"

Related: Tunable asymmetric hysteresis loop: Researchers develop method to control magnetic reversal in Weyl semimetal
https://phys.org/news/2025-03-tunable-asymmetric-hysteresis-loop-method.html#google_vignette