ScholarWorks@성균관대학교

초록

We demonstrate symmetry-selective control of nonlinear photoconductivity in monolayer MoSe2, where near-resonant, linearly polarized light induces transition-specific symmetry breaking and topological phase transitions without violating time-reversal symmetry. Combining Floquet theory with first-principles modeling, we show that x-polarized light breaks both the threefold rotation C3 and the antiunitary mirror TMx$\mathcal{T}{M}_x$, whereas y-polarized light preserves TMx$\mathcal{T}{M}_x$, enabling polarization-resolved generation of interband Berry curvature dipoles. This selective symmetry breaking yields a circular photogalvanic current whose direction and magnitude are tunable via the pump frequency, offering a direct ultrafast probe of Floquet-induced band inversion. These findings establish a viable pathway for detecting light-driven topological currents in nonchiral two-dimensional semiconductors and advancing terahertz optoelectronic applications.

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