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Xueyong Wei

Publications and source records attributed to Xueyong Wei.

4 recordsLinked to original sources

Real-space imaging reveals symmetry-selected nonlinear energy routing in a mechanical resonator

Nonlinear energy routing among modes underlies phenomena ranging from internal resonance and wave mixing to frequency-comb generation in micro- and nanoelectromechanical resonators, yet modal interactions are typically inferred from spectra rather than imaged in real space. This leaves unresolved how energy is spatially routed and what determines which pathways are selected. Here, we use phase-locked multi-harmonic stroboscopic interferometry to reconstruct harmonic-resolved differential displacement maps in a nearly mirror-symmetric microelectromechanical resonator. These maps reveal that harmonics generated by a driven mode can be carried by distinct spatial eigenmodes, directly resolving pathways of nonlinear energy transfer. We further show that such mode-selective routing occurs even away from integer frequency matching: generated harmonics are dominated by eigenmodes sharing the driven mode's mirror parity, whereas spectrally closer opposite-parity modes remain strongly suppressed. A nonlinear modal framework links this hierarchy to symmetry-dependent modal-overlap integrals. These results identify spatial symmetry as a selection rule for nonlinear energy routing.

physics.optics

Ultrasensitive charge detection utilizing coupled nonlinear micromechanical resonators

Since the discovery of electrons, an accurate detection of electrical charges has been the dream of scientific community. Due to some remarkable advantages, micro/nano-electromechanical systems (M/NEMS) based resonators have been used to design electrometers with exquisite sensitivity and resolution. Inevitably, some limits including requisite ultra-low environmental temperature, complicated resonator structure and measurement circuit, required linear dynamic response, will cause a gap with respect to practical application. Here, we demonstrate a novel ultra-sensitive charge detection based on the linear dependence of peak frequency drift on the coupling voltage variation of two coupled nonlinear micromechanical resonators. We achieved ultra-high resolution of 2.051E-3 fC (about 13 electrons) of charge detection at the room temperature. We also show an extra application of this device for weak and ultra-low-frequency (ULF) signal detection. Our findings provide a simple strategy for measuring electron charges in an extreme accuracy and developing electrometers in smaller sizes.

cond-mat.mes-hall

Analysis of the manufacturing variation in a coupled micro resonators array based on its designed value and measured eigenfrequencies

Manufacturing variation in the micro fabrication process inevitably alters the size of the designed structure and thereafter influences the performance of devices to some extent. A good knowledge of this effect will help the design and optimization of the devices. In this letter, we propose an analytical model to investigate the effect of manufacturing variation on the individual resonator in a chain of coupled micro mechanical resonators. The model is also used in a reverse manner to estimate the possible range of manufacturing variation based on the designed value and the measured frequency response.

cond-mat.mes-hall

Temperature dependent electrical resistivity of a single strand of ferromagnetic single crystalline nanowire

We have measured the electrical resistivity of a single strand of a ferromagnetic Ni nanowire of diameter 55 nm using a 4-probe method in the temperature range 3 K-300 K. The wire used is chemically pure and is a high quality oriented single crystalline sample in which the temperature independent residual resistivity is determined predominantly by surface scattering. Precise evaluation of the temperature dependent resistivity ($ρ$) allowed us to identify quantitatively the electron-phonon contribution (characterized by a Debye temperature $θ_R$) as well as the spin-wave contribution which is significantly suppressed upon size reduction.

cond-mat.mes-hall