The rise of topological insulators in recent years has broken new ground both in the conceptual cognition of condensed matter physics and the promising revolution of the electronic devices.It also stimulates the explo...The rise of topological insulators in recent years has broken new ground both in the conceptual cognition of condensed matter physics and the promising revolution of the electronic devices.It also stimulates the explorations of more topological states of matter.Topological crystalline insulator is a new topological phase,which combines the electronic topology and crystal symmetry together.In this article,we review the recent progress in the studies of SnTe-class topological crystalline insulator materials.Starting from the topological identifications in the aspects of the bulk topology,surface states calculations,and experimental observations,we present the electronic properties of topological crystalline insulators under various perturbations,including native defect,chemical doping,strain,and thickness-dependent confinement effects,and then discuss their unique quantum transport properties,such as valley-selective filtering and helicity-resolved functionalities for Dirac fermions.The rich properties and high tunability make SnTe-class materials promising candidates for novel quantum devices.展开更多
Time-periodic laser driving can create nonequilibrium states not accessible in equilibrium,opening new regimes in materials engineering and topological phase transitions.We report that black phosphorus(BP)exhibits spa...Time-periodic laser driving can create nonequilibrium states not accessible in equilibrium,opening new regimes in materials engineering and topological phase transitions.We report that black phosphorus(BP)exhibits spatially nonuniform topological Floquet-Dirac states under laser illumination,mimicking the"gravity"felt by fermionic quasiparticles in the same way as that for a Schwarzschild black hole(SBH).Quantum tunneling of electrons from a type-ⅡDirac cone(inside BH)to a type-ⅠDirac cone(outside BH)emits an SBH-like Planck radiation spectrum.The Hawking temperature T_H obtained for a fermionic analog of BH in the bilayer BP is approximately 3K,which is several orders of magnitude higher than that in previous works.Our work sheds light on increasing T_H from the perspective of engineering 2D materials by time-periodic light illumination.The predicted SBH-like Hawking radiation,accessible in BP thin films,provides clues to probe analogous astrophysical phenomena in solids.展开更多
基金Project supported by the Ministry of Science and Technology of China(Grant No.2016YFA0301000)the National Natural Science Foundation of China(Grant No.11334006)
文摘The rise of topological insulators in recent years has broken new ground both in the conceptual cognition of condensed matter physics and the promising revolution of the electronic devices.It also stimulates the explorations of more topological states of matter.Topological crystalline insulator is a new topological phase,which combines the electronic topology and crystal symmetry together.In this article,we review the recent progress in the studies of SnTe-class topological crystalline insulator materials.Starting from the topological identifications in the aspects of the bulk topology,surface states calculations,and experimental observations,we present the electronic properties of topological crystalline insulators under various perturbations,including native defect,chemical doping,strain,and thickness-dependent confinement effects,and then discuss their unique quantum transport properties,such as valley-selective filtering and helicity-resolved functionalities for Dirac fermions.The rich properties and high tunability make SnTe-class materials promising candidates for novel quantum devices.
基金Supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0300902 and2016YFA0202300)the National Basic Research Program of China(Grant No.2015CB921001)+2 种基金the National Natural Science Foundation of China(Grant Nos.1177439691850120 and 11974045)the Strategic Priority Research Program(B)of CAS(Grant Nos.XDB30000000 and XDB330301)supported by U.S.DOE-BES(Grant No.DE-FG02-04ER46148)。
文摘Time-periodic laser driving can create nonequilibrium states not accessible in equilibrium,opening new regimes in materials engineering and topological phase transitions.We report that black phosphorus(BP)exhibits spatially nonuniform topological Floquet-Dirac states under laser illumination,mimicking the"gravity"felt by fermionic quasiparticles in the same way as that for a Schwarzschild black hole(SBH).Quantum tunneling of electrons from a type-ⅡDirac cone(inside BH)to a type-ⅠDirac cone(outside BH)emits an SBH-like Planck radiation spectrum.The Hawking temperature T_H obtained for a fermionic analog of BH in the bilayer BP is approximately 3K,which is several orders of magnitude higher than that in previous works.Our work sheds light on increasing T_H from the perspective of engineering 2D materials by time-periodic light illumination.The predicted SBH-like Hawking radiation,accessible in BP thin films,provides clues to probe analogous astrophysical phenomena in solids.
