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Updated: Nov 1, 2025

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures
Published on: October 9, 2012
Gap-Opening Transition in Dirac Semimetal ZrTe_{5}
Yefan Tian1, Nader Ghassemi1, Joseph H Ross1
1Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA.
Abstract:
We apply ^{125}Te nuclear magnetic resonance (NMR) spectroscopy to investigate the Dirac semimetal ZrTe_{5}. With the NMR magnetic field parallel to the b axis, we observe significant quantum magnetic effects. These include an abrupt drop at 150 K in spin-lattice relaxation rate. This corresponds to a gap-opening transition in the Dirac carriers, likely indicating the onset of excitonic pairing. Below 50 K, we see a more negative shift for the Te_{z} bridging site, indicating the repopulation of Dirac levels with spin polarized carriers at these temperatures. This is the previously reported 3D quantum Hall regime; however, we see no sign of a charge density wave as has been proposed.
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