  Noble metals that currently dominate the fields of plasmonics and
metamaterials suffer from large ohmic losses. New plasmonic materials, such as
doped oxides and nitrides, have smaller material loss, and, using them in place
of metals carries promise of reduced-loss plasmonic and metamaterial
structures, with sharper resonances and higher field concentration. This
promise is put to a rigorous analytical test in this work which reveals that
having low material loss is not sufficient to have a reduced modal loss in
plasmonic structures. To reduce the modal loss it is absolutely necessary for
the plasma frequency to be significantly higher than the operational frequency.
Using examples of nanoparticle plasmons and gap plasmons one comes to the
conclusion that even in the mid-infrared spectrum metals continue to hold
advantage over the alternative media. The new materials may still find
application niche where the high absorption loss is beneficial, e.g. in
medicine and thermal photovoltaics.
