Designing Phase Diagrams of High-Temperature Superconductors Using Uniaxial Stress and Hydrostatic Pressure
Zurab Guguchia
Paul Scherrer Institute
Understanding the interplay between charge-stripe, spin-stripe, and superconducting orders is fundamental to deciphering the microscopic pairing mechanism in cuprate high-temperature superconductors. These intertwined orders, which emerge prominently in the stripe phase, provide a unique platform for exploring the complex physics of competing and coexisting quantum states. To this end, we systematically investigate the tunability of spin order, charge order, superconductivity, and crystal structure in the cuprate La2-xBaxCuO4 (LBCO), focusing on doping levels near x=1/8, specifically x=0.115, 0.125 and 0.135 [1-4]. By employing complementary experimental techniques, including muon-spin rotation, AC susceptibility, electrical resistivity, and X-ray diffraction, we aim to elucidate how strain can be utilized as a tool to manipulate these intertwined orders.
In this presentation, I will briefly introduce the muon-spin rotation (μSR) technique and the external tuning parameters we have developed and employed in combination with complementary probes. I will then provide an overview of the effects of both in-plane and out-of-plane strain on stripe-ordered LBCO [1-4], highlighting how strain influences superconductivity, spin-stripe order, and their coexistence, with particular emphasis on the pronounced anisotropy of these responses. I will also draw brief parallels to nickelate systems [5], where superconductivity and charge order have recently gained significant attention. Together, these results provide useful insight into the sensitivity of stripe phases to external perturbations and may help refine our understanding of the mechanisms underlying high-temperature superconductivity.
1. Z. Guguchia et. al., Physical Review Letters 125, 097005 (2020).
2. Z. Guguchia et. al., PNAS 121(1), e2303423120 (2024).
3. S.S. Islam, et. al. and Z. Guguchia, Communications Physics 8, 291 (2025).
4. L. Thomarat et. al. and Z.. Guguchia, G. Simutis, Communications Physics 7, 271 (2024).
5. R. Khasanov et. al. and Z. Guguchia, Nature Physics 21, 430 (2025).