Zero index materials where sound propagates without phase variation, holds a great potential for wavefront and dispersion engineering. Recently explored electromagnetic double zero index metamaterials consist of periodic scatterers whose refractive index is significantly larger than that of the surrounding medium... [Read More]
The cold universe is a vast but freely available heat sink that has been largely neglected in the past and has a great potential to store and dissipate the enormous waste heat we generate every day on Earth... [Read More]
We crystallize up to 15 40Ca+ ions in a ring with a microfabricated silicon surface Paul trap. Delocalization of the Doppler laser-cooled ions shows that the translational symmetry of the ion ring is preserved at millikelvin temperatures. By characterizing the collective motion of the ion crystals, we identify homogeneous electric fields as the dominant symmetry-breaking mechanism at this energy scale... [Read More]
In electrically conductive solids, the Wiedemann-Franz law requires the electronic contribution to thermal conductivity to be proportional to electrical conductivity. Violations of the Wiedemann-Franz law are typically an indication of unconventional quasiparticle dynamics, such as inelastic scattering... [Read More]
Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points... [Read More]
|M. Dubois, C. Shi, X. Zhu, Y. Wang & X. Zhang, "Observation of acoustic Dirac-like cone and double zero refractive index." Nature Communications, 8, 2017.|
|X. Zhang, "Metamaterials for perpetual cooling at large scales." Science, 335, 2017.|
|K. Hippalgaonkar, Y. Wang, Y. Ye, D. Y. Qiu, H. Zhu, Y. Wang, J. Moore, S. G. Louie & X. Zhang, "High thermoelectric power factor in two-dimensional crystals of MoS2." Physical Review B, 95, 2017.|
|P. Zhang, D. Gallardo, S. Liu, Y. Gao, T. Li, Y. Wang, Z. Chen & X. Zhang, "Vortex degeneracy lifting and Aharonov-Bohm-like interference in deformed photonic graphene." Optics Letters, 42, 2017.|
|H.-K. Li, E. Urban, C. Noel, A. Chuang, Y. Xia, A. Ransford, B. Hemmerling, Y. Wang, T. Li, H. Häffner & X. Zhang, "Realization of Translational Symmetry in Trapped Cold Ion Rings." Physical Review Letters, 118, 2017.|
May 2016: Professor Zhang has won the 2016 Julius Springer Prize for Applied Physics
May 2016: Our recent work on metamaterials was highlighted in LBL News.
Apr 2016: Our recent work on valleytronics was highlighted in LBL News.