Unambiguous Identification of Three<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>-Decaying Isomers in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mrow><mml:mi>Cu</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mn>70</mml:mn></mml:mmultiscripts></mml:math>

Using resonant laser ionization, $\ensuremath{\beta}$-decay studies, and for the first time mass measurements, three $\ensuremath{\beta}$-decaying states have been unambiguously identified in $^{70}\mathrm{Cu}$. A mass excess of $\ensuremath{-}62\text{ }976.1(1.6)\text{ }\mathrm{keV}$ and a half-life of 44.5(2) s for the $({6}^{\ensuremath{-}})$ ground state have been determined. The level energies of the $({3}^{\ensuremath{-}})$ isomer at 101.1(3) keV with ${T}_{1/2}=33(2)\text{ }\mathrm{s}$ and the ${1}^{+}$ isomer at 242.4(3) keV with ${T}_{1/2}=6.6(2)\text{ }\mathrm{s}$ are confirmed by high-precision mass measurements. The low-lying levels of $^{70}\mathrm{Cu}$ populated in the decay of $^{70}\mathrm{Ni}$ and in transfer reactions compare well with large-scale shell-model calculations, and the wave functions appear to be dominated by one proton--one neutron configurations outside the closed $Z=28$ shell and $N=40$ subshell. This does not apply to the ${1}^{+}$ state at 1980 keV which exhibits a particular feeding and deexcitation pattern not reproduced by the shell-model calculations.