Tuning a coupled phase transition in nickelate thin films using helium ion implantation*

Coupling of lattice, charge and spin degrees of freedom in strongly correlated electron systems of rare earth nickelates leads to the concurrent first order phase transition from a paramagnetic metal to a bond-ordered antiferromagnetic insulator in NdNiO₃ and PrNiO₃. Identification of the driving electronic degree of freedom of this phase transition is still debated. Here we will show how increasing helium ion implantation to epitaxially grown films can act as a tuning knob to gradually suppress the phase transition. Then we will follow up with experimental results detailing the effect of helium ion implantation on individual electronic degrees of freedom. We will conclude our discussion with important insights on the coupled first order phase transition.