Vanishing quantum oscillations in Dirac semimetal ZrTe ₅

Abstract

One of the characteristics of topological materials is their nontrivial Berry phase. Experimental determination of this phase largely relies on a phase analysis of quantum oscillations. We study the angular dependence of the oscillations in a Dirac material [Formula: see text] and observe a striking spin-zero effect (i.e., vanishing oscillations accompanied with a phase inversion). This indicates that the Berry phase in [Formula: see text] remains nontrivial for arbitrary field direction, in contrast with previous reports. The Zeeman splitting is found to be proportional to the magnetic field based on the condition for the spin-zero effect in a Dirac band. Moreover, it is suggested that the Dirac band in [Formula: see text] is likely transformed into a line node other than Weyl points for the field directions at which the spin zero occurs. The results underline a largely overlooked spin factor when determining the Berry phase from quantum oscillations.

Topological metals induced by the Zeeman effect

“…Inset is a schematic illustration of the geometry for axes. The FS is an ellipsoid with principal semi-axes ka=0.118 nm −1 ,k b =0.666 nm −1 and kc=0.153 nm −1 which agrees well with the experiments [34].…”

“…With the parameters given in Ref. [3], we calculate the oscillation amplitude factor of the oscillation R s for all the field directions as illustrated in Fig.1, from which we can obtain the angles of "spin-zero" which are summarized and compared with experiments [34] in Table.I. The theoretical results are consistent with the experimental results only when the Berry phase contributions are included.…”

“…And the angles measured in Ref. [34] are indicated by green dotted line. We only keep linear approximation of k because of the tiny FS in ZrTe5.…”

Zeeman-splitting-induced topological nodal structure and anomalous Hall conductivity in ZrTe5

“…This is because each 2D plane parallel to the ac plane which lies between the two Weyl points contributes Chern number of χ or −χ to the integral in Eq. (16), whereas the planes which do not lie between the two Weyl points have zero Chern number. In this case, the intrinsic AHC is simply proportional to the separation between the Weyl points along the b axis.…”

“…The sensitivity of the topological phase to small changes of the lattice constant or temperature, places this material as an ideal playground for exploring effects of external stimuli on topological properties. Furthermore, such sensitivity resulted in experimental observations of weak TI 4,11,12 , strong TI 4,13 , and Dirac semimetal phases [14][15][16] in 3D ZrTe 5 .…”