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Welcome to Jun Zhao's group!
We use various neutron scattering techniques, along with other probes including X-ray scattering and transport measurements, to study strongly correlated systems, such as unconventional superconductors, low-dimensional magnets, frustrated systems and other transition-metal or rare-earth materials. Our research focus is on investigating crystal structures, magnetic structures, spin excitations and phase transitions of these systems.










Group News
There are currently openings for graduate students and postdoctoral fellows in our group.
The normal duration of the postdoctoral fellow is two years at an annual salary of 210000 CNY.
Interested students please write to Prof. Zhao (zhaoj(at)fudan.edu.cn)
[December 2016]
A picture of Yu Feng doing experiment has been selected as cover of the annual review of the ISIS Neutron and Muon Source for 2016.more









[December 2016]
Our group published a paper entitled "Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate" on Nature [Nature 540, 559-562 (2016)]. In this work, we used inelastic neutron scattering to study the quantum spin liquid candidate YbMgGaO4 and found broad spin excitations covering a wide region of the Brillouin zone. The observed diffusive spin excitation persists at the lowest measured energy and shows a clear upper excitation edge, consistent with the particle–hole excitation of a spinon Fermi surface. Our results therefore point to the existence of a quantum spin liquid state with a spinon Fermi surface in YbMgGaO4, which has a perfect spin-1/2 triangular lattice as in the original proposal of quantum spin liquids.more
[July 2016]
Our group published a paper entitled "Magnetic ground state of FeSe" on Nature Communications [Nature Communications 7, 12182 (2016)]. In this work, we report inelastic neutron-scattering experiments in FeSe single crystals that reveal both stripe and Neel spin fluctuations over a wide energy range at 110 K. On entering the nematic phase, a substantial amount of spectral weight is transferred from the Neel to the stripe spin fluctuations. Moreover, the total fluctuating magnetic moment of FeSe is about 60% larger than that in the iron pnictide BaFe2As2. Our results suggest that FeSe is a novel S=1 nematic quantum-disordered paramagnet interpolating between the Neel and stripe magnetic instabilities.more
[May 2016]
Our group published a paper entitled "Transition from Sign-Reversed to Sign-Preserved Cooper-Pairing Symmetry in Sulfur-Doped Iron Selenide Superconductors" on Physical Review Letters [Phys. Rev. Lett. 116, 197004 (2016)]. In this work, we observed that a rather sharp magnetic resonant mode well below the superconducting gap (2\Delta) in the undoped iron selenide superconductors KxFe2−y(Se1−zSz)2 (z=0) is replaced by a broad hump structure above 2\Delta under 50 percent sulfur doping (z=0.5), indicatinga transition from the sign-reversed to sign-preserved Cooper-pairing symmetry with insignificant changes in Tc.more
[February 2016]
Our group published a paper entitled "Strong interplay between stripe spin fluctuations, nematicity and superconductivity in FeSe" on Nature Materials [Nature Materials 15, 159–163 (2016)]. In this work, we study FeSe by neutron scattering, finding substantial stripe spin fluctuations coupled with the nematicity that are enhanced abruptly on cooling through Ts. A sharp spin resonance develops in the superconducting state, whose energy (about 4 meV) is consistent with an electron–boson coupling mode revealed by scanning tunnelling spectroscopy. The magnetic spectral weight in FeSe is found to be comparable to that of the iron arsenides. Our results support recent theoretical proposals that both nematicity and superconductivity are driven by spin fluctuations.more
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Contact: yaoshen13(at)fudan.edu.cn