Abstract
Dirac semimetals have attracted extensive attentions in recent years. It has been theoretically suggested that many-body interactions may drive exotic phase transitions, spontaneously generating a Dirac mass for the nominally massless Dirac electrons. So far, signature of interaction-driven transition has been lacking. In this work, we report high-magnetic-field transport measurements of the Dirac semimetal candidate ZrTe5. Owing to the large g factor in ZrTe5, the Zeeman splitting can be observed at magnetic field as low as 3 T. Most prominently, high pulsed magnetic field up to 60 T drives the system into the ultra-quantum limit, where we observe abrupt changes in the magnetoresistance, indicating field-induced phase transitions. This is interpreted as an interaction-induced spontaneous mass generation of the Dirac fermions, which bears resemblance to the dynamical mass generation of nucleons in high-energy physics. Our work establishes Dirac semimetals as ideal platforms for investigating emerging correlation effects in topological matters.
Highlights
Dirac semimetals have attracted extensive attentions in recent years
For Dirac and Weyl semimetals, it has been theoretically suggested that a high-magnetic field may induce the dynamical mass generation[30,31,32,33,34], namely, a Dirac mass is spontaneously generated by interaction effects
The mass generation has been observed at the surface of two-dimensional (2D) topological crystalline insulators[36,37], so far there is no clear evidence of its occurrence in threedimensional bulk Dirac materials, despite its closer resemblance to that occurring in particle physics[38]
Summary
Dirac semimetals have attracted extensive attentions in recent years. It has been theoretically suggested that many-body interactions may drive exotic phase transitions, spontaneously generating a Dirac mass for the nominally massless Dirac electrons. Both singlefrequency[5,6] and multi-frequency[4] Shubnikov–de Haas (SdH) oscillations were reported in ZrTe5, suggesting a strong dependency of the electron states on the Fermi energy, EF, in the band structure This material was reinvestigated as a candidate of Dirac semimetal[7]. The generated Dirac mass endows an energy gap to the nominally massless Dirac electrons, causing sharp increase in the resistivity These findings suggest ZrTe5 a versatile platform for searching novel correlated states in Dirac semimetal and show the possibility on field-controlled novel symmetry-breaking phases manifesting the Dirac mass in the study of Dirac and Weyl semimetals
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