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]
Lasing, light amplification by stimulated emission of radiation, is a key attribute for many important applications in optical communications, medicine and defence. Conversely, anti-lasing represents the time-reversed counterpart of laser emission, where incoming radiation is coherently absorbed... [Read More]
Next-generation electronics calls for new materials beyond silicon, aiming at increased functionality, performance and scaling in integrated circuits. In this respect, two-dimensional gapless graphene and semiconducting transition-metal dichalcogenides... [Read More]
|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, 2016.|
|S. Lee, K. Hippalgaonkar, F. Yang, J. Hong, C. Ko, J. Suh, K. Liu, K. Wang, J. J. Urban, X. Zhang, C. Dames, S. A. Hartnoll, O. Delaire & J. Wu, "Anomalously low electronic thermal conductivity in metallic vanadium dioxide." Science, 335, 2016.|
|S. R. Sklan, X. Bai, B. Li & X. Zhang, "Detecting Thermal Cloaks via Transient Effects." Scientific Reports, 6, 2016.|
|Z. Chen, X. Wang, Y. Qi, S. Yang, J. A. N. T. Soares, B. A. Apgar, R. Gao, R. Xu, Y. Lee, X. Zhang, J. Yao & L. W. Martin, "Self-Assembled, Nanostructured, Tunable Metamaterials via Spinodal Decomposition." ACS Nano, 10, 2016.|
|J.-W. Dong, X.-D. Chen, H. Zhu, Y. Wang & X. Zhang, "Valley photonic crystals for control of spin and topology." Nature Materials, AOP, 2016.|
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.