Emergence of a spin-liquid-like phase in the quantum spin ladder compound Ba2CuTeO6 with chemical substitution

The stabilization of quantum spin liquids is vital to realize applications in spintronics and quantum computing. The unique magnetic structure of Ba₂CuTeO₆ comprising coupled spin ladders with finite interladder coupling brings the system close to the quantum critical point. This opens up possibilities to stabilize unconventional magnetic phases by tailoring the intra- and interladder exchange couplings. Here, we demonstrate a spin-liquid-like phase in Ba₂CuTeO₆ using the method of chemical substitution. We choose nonmagnetic La³⁺ cation to substitute the Ba²⁺ in Ba₂CuTeO₆ and present signature fingerprints such as a deprived magnetic transition, nondispersive ac susceptibility, magnetic-field-independent heat capacity, and a broad Raman continuum supporting the emergence of a spin-liquid-like phase. We believe that increased magnetic frustration and spin fractionalization upon chemical substitution play a crucial role in driving such a state. In addition, temperature and magnetic-field-dependent phonon responses indicate the presence of magnetostriction (spin-lattice coupling) in La-doped Ba₂CuTeO₆, a notable property of spin liquids.