Zeeman splitting and dynamical mass generation in Dirac semimetal ZrTe5

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.

Nearly massless Dirac fermions and strong Zeeman splitting in the nodal-line semimetal ZrSiS probed by de Haas–van Alphen quantum oscillations

“…This effect is expected to be particularly strong for the α-Dirac band of ZrSiS since the quantum limit of this band can be easily reached due to its low oscillation frequency (F α ~8.4T). Although our SQUID magnetometer can only reach 7T, the second Landau level can be reached and our experimentally observed large g-factor in ZrSiS is in line with the anticipated enhanced electronic correlation effects, as seen in ZrTe 5 [91]. Indeed, the recent high field SdH studies has revealed usually mass enhancement at low temperatures, which seems consistent with the enhanced correlation in ZrSiS [56].…”

“…In general, for a system showing Landau level quantization, the increased degeneracy of Landau levels leads to enhanced density of state near the Fermi level under high magnetic fields, which effectively amplifies the electron correlation effect [90][91][92]. This effect is expected to be particularly strong for the α-Dirac band of ZrSiS since the quantum limit of this band can be easily reached due to its low oscillation frequency (F α ~8.4T).…”

Observation of Optical and Electrical In-Plane Anisotropy in High-Mobility Few-Layer ZrTe5

“…The extracted effective mass is 0.032me which is very close to the results in other works 10, 16,17,19 .…”

Thermodynamic signature of Dirac electrons across a possible topological transition in ZrTe5

“…In this study we focus on ZrTe 5 , a material whose topological nature is hotly debated; it has been predicted and verified as a Dirac semimetal [4][5][6][7][8], a topological insulator [9][10][11][12] and a trivial semiconductor [13,14]. In addition to its potential topological nature, there is also an unusual anomaly in the temperature dependence of the resistivity that has been conjectured to originate from a Lifshitz transition [15,16].…”

“…Hall effect data shows electron-like carriers at low temperature [16], implying some of these additional bands must be populated and Dirac-like or massive Dirac-like features should be present. Note that these features are extremely sensitive to cell volume and strain [17], which may explain the conflicting experimental reports on the electronic properties and topological signatures in ZrTe 5 [4][5][6][7][8][9][10][11][12][13][14].…”