  Recently, it has been rigorously verified that several one-dimensional (1D)
spin models may exhibit a peculiar pseudo-transition accompanied with anomalous
response of thermodynamic quantities in a close vicinity of pseudo-critical
temperature. In the present work we will introduce and exactly solve a mixed
spin-(1/2,1) Ising-Heisenberg double-tetrahedral chain in an external magnetic
field as another particular example of 1D lattice-statistical model with
short-range interactions that displays a pseudo-transition of this type. The
investigated model exhibits at zero temperature three ferrimagnetic phases,
three frustrated phases, and one saturated paramagnetic phase. The ground-state
phase diagram involves five unusual interfaces (phase boundaries), at which the
residual entropy per site equals to a larger entropy of one of two coexisting
phases. Four such interfaces are between a non-degenerate ferrimagnetic phase
and a macroscopically degenerate frustrated phase, while one interface is
between two non-degenerate ferrimagnetic phases. Though thermal excitations
typically destroy all fingerprints of zero-temperature phase transitions of 1D
lattice-statistical models with short-range forces, the mixed spin-(1/2,1)
Ising-Heisenberg double-tetrahedral chain is quite robust with respect to
thermal excitations and it displays peculiar pseudo-transitions close to all
five aforementioned interfaces.
