  Lifshitz transition represents a sudden reconstruction of Fermi surface
structure, giving rise to anomalies in electronic properties of materials. Such
a transition does not necessarily rely on symmetry-breaking and thus is
topological. It holds a key to understand the origin of many exotic quantum
phenomena, for example the mechanism of extremely large magnetoresistance (MR)
in topological Dirac/Weyl semimetals. Here, we report studies of the
angle-dependent MR (ADMR) and the thermoelectric effect in W2As3 single
crystal. The compound shows a large unsaturated MR (of about 70000% at 4.2 K
and 53 T). The most striking finding is that the ADMR significantly deforms
from the horizontal dumbbell-like shape above 40 K to the vertical lotus-like
pattern below 30 K. The window of 30-40 K also corresponds substantial changes
in Hall effect, thermopower and Nernst coefficient, implying an abrupt change
of Fermi surface topology. Such a temperature-induced Lifshitz transition
results in a compensation of electron-hole transport and the large MR as well.
We thus suggest that the similar method can be applicable in detecting a
Fermi-surface change of a variety of quantum states when a direct Fermi-surface
measurement is not possible.
