arXiv subjects

Zhuo-Cheng Gu

Publications and source records attributed to Zhuo-Cheng Gu.

3 recordsLinked to original sources

arXiv2026

Electrical control of spin photocurrent in a magnetoelectric oxide Cr$_2$O$_3$

Controlling magnetism by electric field or current is a central topic in spintronics. In this work, we argue that the magnon spin photocurrent can also be controlled by the electric field in magnetoelectrics. Taking Cr$_2$O$_3$ as an example, we demonstrate how the spin current is modified by the electric field, using nonlinear response theory. We find that the Dzyaloshinsky--Moriya interaction induced by the applied field plays a key role in modifying spin-current conductivity, which exhibits pronounced anisotropy with respect to the light polarization. In particular, both the resonance frequency and the peak intensity show distinct dependences on the external electric field $E$, demonstrating electrical control of the spin photocurrent. In addition, we show that the two-magnon processes give rise to a continuum spectrum, a consequence of the field-induced spin canting. These results show that Cr$_2$O$_3$ is a promising platform for realizing electrically tunable spin photovoltaic effect.

cond-mat.mes-hall↗

arXiv2025

Controlling resonant spin photocurrent using magnetic field; application to a magnetoelectric oxide Cr2O3

We study the magnon spin photocurrent in effective spin models for Cr2O3, a material known for its magnetoelectric effect. Using nonlinear response theory, we show that magnon spin current can be generated by both linearly and circularly polarized electromagnetic waves via one-magnon processes. While linearly polarized waves induce a spin current even in the absence of a static magnetic field, circularly polarized waves lead to a spin current only when a static field is present, and the current reverses its direction upon field inversion. The distinct dependence on the external magnetic field and the contrasting responses to different polarizations allow the spin photocurrent to be differentiated from competing effects such as spin pumping or inhomogeneous heating, facilitating experimental verification. These results suggest that Cr2O3 is a promising candidate for experimental studies of magnon photocurrent.

cond-mat.mes-hall↗

arXiv2025

Manipulating spectral transitions and photonic transmission in a non-Hermitian optical system through nanoparticle perturbations

In recent years, extensive research has been dedicated to the study of parity-time ($\mathcal{PT}$) symmetry, which involves the engineered balance of gain and loss in non-Hermitian optics. Complementary to $\mathcal{PT}$ symmetry, the concept of anti-$\mathcal{PT}$ symmetry has emerged as a natural framework for describing the dynamics of open systems with dissipations. In this work, we study spectral transitions and photon transmission in a linear spinning resonator perturbed by nanoparticles. First, we show that by precisely controlling the nanoparticle perturbations, the eigenvalues (or spectra) of a non-Hermitian system satisfying anti-$\mathcal{PT}$ symmetry can transit to that of a quasi-closed Hermitian system. Second, we outline the essential conditions for constructing a quasi-closed system and analyze its dynamic behavior with respect to photon transmission. By adjusting the rotational angular velocity of the spinning resonator and the strength of the nanoparticle perturbations, the quasi-closed system enables a variety of photon distribution behaviors, which may have significant applications in quantum devices. Our findings offer valuable insights for the design of dissipative quantum devices under realistic conditions and for understanding their responses to external perturbations.

physics.optics↗