Education and Working History

Research History

Understanding on vortex matter in type II superconductivity has experienced great progress since the discovery of high-Tc superconductivity in cuprates. Xiao Hu and his co-workers were the first in the world to clarify successfully the first-order melting transition of the vortex lattice using Monte Carlo simulation. His work in 1997 clearly showed that the vortex lattice melting coincides with the phase transition between superconductivity and normal state. According to text book on high-Tc superconductivity, this contribution is one of the milestones in this field, following others such as the proposal of vortex state by Abrikosov (who got the Nobel Prize in 2003), the proposal to observe vortex lattice melting in high-Tc cuprates (Nelson and Gammel). After that Xiao Hu has made systematic investigations on vortex states, such as the effect of point-like defects on the phase diagram, novel phases and phase diagram of interlayer Josephson vortices, scaling properties of current-driven vortex matter. In contrast to previous theory, Xiao Hu and his co-authors predicted that for interlayer Josephson vortices the smectic phase can only happen with period 2, and in a narrow region of temperature about 1 Kelvin. The theoretical prediction has been verified by a cutting-edge experiment recently. Xiao Hu and his collaborators have also performed large-scale computer simulation for a novel technique, which uses single crystal of high-Tc superconductor to excite terahertz electromagnetic radiation. They clarified the mechanism of emission, and evaluated the power of electromagnetic wave and the power spectrum, and thus verified the feasibility of the technique. Due to his achievements he is regarded as one of the world-wide leading scientists in the field of vortex states of superconductivity.

Selected Papers

1. Luo M B, Hu X, 'Depinning and creep motion in glass states of flux lines', Phys. Rev. Lett., 98, (2007) 267002
2. Wan X G, Kohno M, Hu X, 'Orbital order and ferrimagnetic properties of the new compound Sr8CaRe3Cu4O24', Phys. Rev. Lett., 94, (2005) 087205
3. Wan X G, Kohno M, Hu X, 'Robust half-metallic character and large oxygen magnetism in a perovskite cuprate', Phys. Rev. Lett., 95, (2005) 146602
4. Hu X, Luo M B, Ma Y Q, 'Density functional theory for freezing transition of vortex-line liquid with periodic layer pinning', Phys. Rev. B, 72, (2005) 174503
5. Hu X, Tachiki M, ' Decoupled two-dimensional superconductivity and continuous melting transitions in layered superconductors under a parallel magnetic field', Phys. Rev. B, 70, (2004) 064506
6. Tanaka A, Hu X, 'Possible spin triplet superconductivity in NaxCoO2/ yH2O', Phys. Rev. Lett., 91, (2003) 257006
7. Tanaka A, Hu X, 'Quantal phases, disorder effects and superconductivity in spin-Peierls systems', Phys. Rev. Lett., 88, (2002), 127004
8. Nonomura Y, Hu X, 'Effects of point defects on the phase diagram of vortex states in high-T-c superconductors in the B || c axis', Phys. Rev. Lett., 86, (2001) 5140.
9. X. Hu, 'Bicritical and tetracritical phenomena and scaling properties of the SO(5) theory', Phys. Rev. Lett., 87, (2001) 057004
10. Hu X, Tachiki M, 'Possible tricritical point in phase diagrams of interlayer Josephson-vortex systems in high-T-c Superconductors', Phys. Rev. Lett., 85, (2000) 257