  Thermalization phenomena, while ubiquitous in quantum systems, have
traditionally been viewed as obstacles to be mitigated. In this study, we
demonstrate the ability, instead, to harness thermalization to dynamically
engineer and stabilize structured quantum states in a mesoscopically large
ensemble of spins. Specifically, we showcase the capacity to generate, control,
stabilize, and read out 'shell-like' spin texture with interacting $ {}^{
13}\mathrm{C}$ nuclear spins in diamond, wherein spins are polarized oppositely
on either side of a critical radius. The texture spans several nanometers and
encompasses many hundred spins. We capitalize on the thermalization process to
impose a quasi-equilibrium upon the generated texture; as a result, it is
highly stable, immune to spin diffusion, and endures over multiple-minute long
periods -- over a million times longer than the intrinsic interaction scale of
the spins. Additionally, the texture is created and interrogated without
locally controlling or probing the nuclear spins. These features are
accomplished using an electron spin as a nanoscale injector of spin
polarization, and employing it as a source of spatially varying dissipation,
allowing for serial readout of the emergent spin texture. Long-time
stabilization is achieved via prethermalization to a Floquet-induced
Hamiltonian under the electronic gradient field. Our work presents a new
approach to robust nanoscale spin state engineering and paves the way for new
applications in quantum simulation, quantum information science, and nanoscale
imaging.
