arXiv subjects

Evan M. Wilson

Publications and source records attributed to Evan M. Wilson.

3 recordsLinked to original sources

arXiv2026

Light induced superconducting diode effect in patterned films

Structured light offers a route to control superconducting transport without permanently modifying the material or applying a static bias. Here we show that structured optical driving can generate a superconducting diode response in patterned superconducting films with asymmetric holes. Using generalized time-dependent Ginzburg Landau simulations, we find that optical driving produces rectified dc photovoltages and zero bias directional supercurrent imbalance in a junction free geometry, with continuous-drive diode efficiencies of order $10^{-3}$ and pulsed efficiencies reaching $10^{-2}$. The response is controlled by both the hole array and the optical mode. Increasing the number of asymmetric holes enhances rectification, reversing circular helicity reverses the diode polarity, and the optical spatial mode strongly modifies the magnitude and polarity of the directional response. Pulsed excitation enhances the zero bias line cut current imbalance to the percent level. For linearly polarized illumination, the asymmetric metacrystal converts the drive into local chiral supercurrent motion, inducing an inverse Faraday effect like mechanism for dynamical time reversal symmetry breaking. These results establish patterned superconducting films as a viable platform for light-tunable superconducting diode behavior.

cond-mat.supr-con↗

arXiv2025

General structure factor and dynamic effects of the Dzyaloshinskii-Moriya interaction in S = 1/2 clusters

Understanding the effects of the Dzyaloshinskii-Moriya interaction (DMI) has become increasingly important in the context of nanoscale magnetism and spintronics. In this study, we derive a general structure factor equation for an S = 1/2 dimer and show that the anisotropic ratio $D_z/|J|$ and complex phase $\phi$ of the DMI control the gap energy and intensity of the $|0,0\rangle \to |1,0\rangle$ transition. {Using exact diagonalization of the Heisenberg spin-spin Hamiltonian that incorporates both isotropic and anisotropic interactions,} as well as the effects of an external magnetic field and an electric field. Our results show that the DM interaction splits energy eigenstates, induces level repulsion, and significantly modifies the spin dimer structure factor. These effects reveal a direct correspondence between thermodynamic anomalies in the heat capacity and spin-resolved selection rules.

cond-mat.mtrl-sci↗

arXiv2025

Exact eigenvalues and experimental signatures of Heisenberg-Kitaev interactions in spin-1/2 quantum clusters

We investigate the thermodynamics and energy eigenstates of a spin-1/2 coupled trimer, tetramer in a star configuration, and tetrahedron. Using a Heisenberg Hamiltonian with additional Kitaev interactions, we explore the thermodynamic signatures of the Kitaev interaction. Our results show that introducing a Kitaev interaction generates a second Schottky anomaly in the heat capacity for systems with a large K/J ratio. The Kitaev term also introduces nonlinear eigenvalues with respect to a magnetic field, pushing the clusters toward a regime similar to the incomplete Paschen-Back effect and triggering first and second-order quantum phase transitions along with robust thermodynamic behavior. Through this approach, we provide exact analytical solutions that offer insights into Kitaev interactions, both in molecular magnets and in extended systems such as honeycomb or Kagome lattices. Furthermore, we provide insight into experimental measurements for detecting Kitaev interactions in clusters.

cond-mat.mtrl-sci↗