High-spin proton alignments and evidence for a second band with enhanced deformation in 171Hf

High-spin properties of the nucleus ${}^{171}$Hf were studied through the ${}^{128}$Te(${}^{48}$Ca,5$n$) reaction. Previously known bands have been extended to significantly higher spins and four new bands have been extracted from these data. The results are discussed within the framework of the cranked shell model aided by a comparison with level structures in the neighboring nuclei. The band crossings at rotational frequencies $\ensuremath{\sim}$500 keV are interpreted as caused by the alignments of ${h}_{11/2}$ and ${h}_{9/2}$ proton orbitals. Band ED2 exhibits an alignment pattern similar to that of band ED1 which was reported in a recent paper and proposed to be built on a second potential energy minimum involving the deformation-driving proton ${i}_{13/2}\ensuremath{\bigotimes}{h}_{9/2}$ configuration. It is likely that band ED2 is also associated with a deformation enhanced with respect to that of the normal deformed structures. Further experimental investigation is needed to ascertain the nature of this band.