Floquet engineering provides a versatile platform for realizing and manipulating diverse exotic topological phases inaccessible in equilibrium.Under the irradiation of circularly or elliptically polarized light,the si...Floquet engineering provides a versatile platform for realizing and manipulating diverse exotic topological phases inaccessible in equilibrium.Under the irradiation of circularly or elliptically polarized light,the sizable spin-orbit couplings in group-IV Xene materials(e.g.,silicene,germanene,stanene)lead to topological phase transitions(TPT)from quantum spin Hall(QSH)to quantum anomalous Hall(QAH)states,governed by spin-degeneracy broken with band closing and reopening process in one of the spin components.Fascinatingly,a large gapped(≥35 meV)QAH effect with a Chern number C=±2 can be introduced under a wide range of laser parameters,lifting limitations of conventional atomic building blocks to achieve long-range magnetism and enabling Chern-insulating behaviors above room temperature.A complex phase diagram for such TPTs is predicted.This work addresses transitions between two-dimensional QSH and QAH states via Floquet engineering,which will stimulate experimental realization of above-room-temperature QAH in group-IV Xenes.展开更多
基金supported by National Natural Science Foundation of China(No.12025407 and No.12450401)National Key Research and Development Program of China(No.2021YFA1400201)Chinese Academy of Sciences(No.YSBR-047 and No.XDB33030100).
文摘Floquet engineering provides a versatile platform for realizing and manipulating diverse exotic topological phases inaccessible in equilibrium.Under the irradiation of circularly or elliptically polarized light,the sizable spin-orbit couplings in group-IV Xene materials(e.g.,silicene,germanene,stanene)lead to topological phase transitions(TPT)from quantum spin Hall(QSH)to quantum anomalous Hall(QAH)states,governed by spin-degeneracy broken with band closing and reopening process in one of the spin components.Fascinatingly,a large gapped(≥35 meV)QAH effect with a Chern number C=±2 can be introduced under a wide range of laser parameters,lifting limitations of conventional atomic building blocks to achieve long-range magnetism and enabling Chern-insulating behaviors above room temperature.A complex phase diagram for such TPTs is predicted.This work addresses transitions between two-dimensional QSH and QAH states via Floquet engineering,which will stimulate experimental realization of above-room-temperature QAH in group-IV Xenes.
