The effect of compression on the magnetic ground state of Sr_{2}IrO_{4} is studied with x-ray resonant techniques in the diamond anvil cell. The weak interlayer exchange coupling between square-planar 2D IrO_{2} layers is readily modified upon compression, with a crossover between magnetic structures around 7 GPa mimicking the effect of an applied magnetic field at ambient pressure. Higher pressures drive an order-disorder magnetic phase transition with no magnetic order detected above 17-20 GPa. The persistence of strong exchange interactions between J_{eff}=1/2 magnetic moments within the insulating IrO_{2} layers up to at least 35 GPa points to a highly frustrated magnetic state in compressed Sr_{2}IrO_{4}, opening the door for realization of novel quantum paramagnetic phases driven by extended 5d orbitals with entangled spin and orbital degrees of freedom.
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http://dx.doi.org/10.1103/PhysRevLett.124.067201 | DOI Listing |
Nat Commun
February 2024
Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Eco-materials and Renewable Energy Research Center (ERERC), College of Engineering and Applied Sciences, Nanjing University, No. 22 Hankou Road, Nanjing, 210093, Jiangsu, PR China.
Compressive strain, downshifting the d-band center of transition metal oxides, is an effective way to accelerate the sluggish kinetics of oxygen evolution reaction (OER) for water electrolysis. Here, we find that anisotropic thermal expansion can produce compressive strains of the IrO octahedron in SrIrO catalyst, thus downshifting its d-band center. Different from the previous strategies to create constant strains in the crystals, the thermal-triggered compressive strains can be real-timely tuned by varying temperature.
View Article and Find Full Text PDFNat Commun
November 2022
Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569, Stuttgart, Germany.
Magnonic devices operating at terahertz frequencies offer intriguing prospects for high-speed electronics with minimal energy dissipation However, guiding and manipulating terahertz magnons via external parameters present formidable challenges. Here we report the results of magnetic Raman scattering experiments on the antiferromagnetic spin-orbit Mott insulator SrIrO under uniaxial stress. We find that the energies of zone-center magnons are extremely stress sensitive: lattice strain of 0.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2020
Photon Science Division, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland;
In the high spin-orbit-coupled SrIrO, the high sensitivity of the ground state to the details of the local lattice structure shows a large potential for the manipulation of the functional properties by inducing local lattice distortions. We use epitaxial strain to modify the Ir-O bond geometry in SrIrO and perform momentum-dependent resonant inelastic X-ray scattering (RIXS) at the metal and at the ligand sites to unveil the response of the low-energy elementary excitations. We observe that the pseudospin-wave dispersion for tensile-strained SrIrO films displays large softening along the [h,0] direction, while along the [h,h] direction it shows hardening.
View Article and Find Full Text PDFJ Phys Condens Matter
June 2018
Department of Physics, University of Colorado at Boulder, CO 80309, United States of America.
We report a systematical structural, transport and magnetic study of Ca or Ba doped SrIrO single crystals. Isoelectronically substituting Ca (up to 15%) or Ba (up to 4%) ion for the Sr ion provides no additional charge carriers but effectively changes the lattice parameters in SrIrO. In particular, 15% Ca doping considerably reduces the c-axis and the unit cell by nearly 0.
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