arXiv subjects

M. Y. Zou

Publications and source records attributed to M. Y. Zou.

3 recordsLinked to original sources

arXiv2026

A study of periodic nulling in PSR B0751+32 with FAST

We report new results from a nulling study of PSR~B0751+32 (PSR J0754+3231), observed at 1250~MHz with the Five hundred meter Aperture Spherical radio Telescope (FAST). Our analysis confirms the presence of periodic nulling in this pulsar. Using the recently developed mixture model method, we obtained a nulling fraction (NF) of $35.1\% \pm 0.6\%$. Three independent approaches were employed to estimate the nulling periodicity, and the results reveal significant temporal evolution of the modulation both within individual observations and across different \textbf{observing} essions. The pulsar exhibits an asymmetric two-component mean pulse profile, with the leading component brighter and narrower than the trailing one. Pulse energy analysis shows that both components remain stable immediately after the onset of the burst state, but subsequently undergo a progressive decline, with the trailing component most severely affected prior to burst termination. Notably, no evidence of the previously reported subpulse drifting was detected in our data. Our results challenge previous models that ascribed periodic nulling to purely geometric effects.

astro-ph.HE↗

arXiv2024

Persistent Spin Dynamics in the Ising Triangular-lattice Antiferromagnet Ba$_6$Nd$_2$Ti$_4$O$_{17}$

We report results of magnetic susceptibility, specific heat, and muon spin relaxation ($μ$SR) measurements on the polycrystalline Ba$_6$Nd$_2$Ti$_4$O$_{17}$, a disorder-free triangular-lattice antiferromagnet. The absence of long-range magnetic order or spin freezing is confirmed down to 30~mK, much less than the Curie-Weiss temperature -1.8~K. The magnetic and specific heat measurements reveal the effective-1/2 spins are Ising-like. The persistent spin dynamics is determined down to 37~mK. Our study present a remarkable example of Ising spins on the triangular lattice, which remains magnetically disordered at low temperatures and potentially hosts a quantum spin liquid ground state.

cond-mat.str-el↗

arXiv2024

Two-Dimensional Phase-Fluctuating Superconductivity in Bulk-Crystalline NdO$_{0.5}$F$_{0.5}$BiS$_2$

We present a combined growth and transport study of superconducting single-crystalline NdO$_{0.5}$F$_{0.5}$BiS$_2$. Evidence of two-dimensional superconductivity with significant phase fluctuations of preformed Cooper pairs preceding the superconducting transition is reported. This result is based on three key observations. (1) The resistive superconducting transition temperature $T_c$ (defined by resistivity $ρ\rightarrow 0$) increases with increasing disorder. (2) As $T\rightarrow T_c$, the conductivity diverges significantly faster than what is expected from Gaussian fluctuations in two and three dimensions. (3) Non-Ohmic resistance behavior is observed in the superconducting state. Altogether, our observations are consistent with a temperature regime of phase-fluctuating superconductivity. The crystal structure with magnetic ordering tendencies in the NdO$_{0.5}$F$_{0.5}$ layers and (super)conductivity in the BiS$_2$ layers is likely responsible for the two-dimensional phase fluctuations. As such, NdO$_{0.5}$F$_{0.5}$BiS$_2$ falls into the class of unconventional ``laminar" bulk superconductors that include cuprate materials and 4Hb-TaS$_2$.

cond-mat.supr-con↗