A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver is built with elastic waves （HLLCE） for one-dimensional elastic-plastic flows with a hypo- elastic constitutive model and the von Mises＇ yielding cr...A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver is built with elastic waves （HLLCE） for one-dimensional elastic-plastic flows with a hypo- elastic constitutive model and the von Mises＇ yielding criterion. Based on the HLLCE, a third-order cell-centered Lagrangian scheme is built for one-dimensional elastic-plastic problems. A number of numerical experiments are carried out. The numerical results show that the proposed third-order scheme achieves the desired order of accuracy. The third-order scheme is used to the numerical solution of the problems with elastic shock waves and elastic rarefaction waves. The numerical results are compared with a reference solution and the results obtained by other authors. The comparison shows that the pre- sented high-order scheme is convergent, stable, and essentially non-oscillatory. Moreover, the HLLCE is more efficient than the two-rarefaction Riemann solver with elastic waves （TRRSE）展开更多
Ultra-thin topological insulators provide a platform for realizing many exotic phenomena such as the quantum spin Hall effect,and quantum anomalous Hall effect.These effects or states are characterized by quantized tr...Ultra-thin topological insulators provide a platform for realizing many exotic phenomena such as the quantum spin Hall effect,and quantum anomalous Hall effect.These effects or states are characterized by quantized transport behavior of edge states.Experimentally,although these states have been realized in various systems,the temperature for the edge states to be the dominating channel in transport is extremely low,contrary to the fact that the bulk gap is usually in the order of a few tens of milli-electron volts.There must be other in-gap conduction channels that do not freeze out until a much lower temperature.Here we grow ultra-thin topological insulator Bi_(2)Te_(3) and Sb_(2)Te_(3)films by molecular beam epitaxy and investigate the structures of domain boundaries in these films.By scanning tunneling microscopy and spectroscopy we find that the domain boundaries with large rotation angles have pronounced in-gap bound states,through which one-dimensional conduction channels are suggested to form,as visualized by spatially resolved spectroscopy.Our work indicates the critical role played by domain boundaries in degrading the transport properties.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11172050 and11672047)the Science and Technology Foundation of China Academy of Engineering Physics(No.2013A0202011)
文摘A Harten-Lax-van Leer-contact （HLLC） approximate Riemann solver is built with elastic waves （HLLCE） for one-dimensional elastic-plastic flows with a hypo- elastic constitutive model and the von Mises＇ yielding criterion. Based on the HLLCE, a third-order cell-centered Lagrangian scheme is built for one-dimensional elastic-plastic problems. A number of numerical experiments are carried out. The numerical results show that the proposed third-order scheme achieves the desired order of accuracy. The third-order scheme is used to the numerical solution of the problems with elastic shock waves and elastic rarefaction waves. The numerical results are compared with a reference solution and the results obtained by other authors. The comparison shows that the pre- sented high-order scheme is convergent, stable, and essentially non-oscillatory. Moreover, the HLLCE is more efficient than the two-rarefaction Riemann solver with elastic waves （TRRSE）
基金Supported by the National Natural Science Foundation of China(Grant Nos.61804056 and 92065102)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics,Tsinghua University.
文摘Ultra-thin topological insulators provide a platform for realizing many exotic phenomena such as the quantum spin Hall effect,and quantum anomalous Hall effect.These effects or states are characterized by quantized transport behavior of edge states.Experimentally,although these states have been realized in various systems,the temperature for the edge states to be the dominating channel in transport is extremely low,contrary to the fact that the bulk gap is usually in the order of a few tens of milli-electron volts.There must be other in-gap conduction channels that do not freeze out until a much lower temperature.Here we grow ultra-thin topological insulator Bi_(2)Te_(3) and Sb_(2)Te_(3)films by molecular beam epitaxy and investigate the structures of domain boundaries in these films.By scanning tunneling microscopy and spectroscopy we find that the domain boundaries with large rotation angles have pronounced in-gap bound states,through which one-dimensional conduction channels are suggested to form,as visualized by spatially resolved spectroscopy.Our work indicates the critical role played by domain boundaries in degrading the transport properties.
