arXiv subjects

L. Mu

Publications and source records attributed to L. Mu.

3 recordsLinked to original sources

arXiv2025

Pressure-induced structural and superconducting transitions in black arsenic

We report high-pressure Raman spectra and resistance measurements of black arsenic (b-As) up to 58 GPa, along with phonon density of states (DOS) and enthalpy calculations for four reported arsenic phases up to 50 GPa. It is found that metastable b-As transforms into gray arsenic (g-As) phase at a critical pressure of 1.51 GPa, followed by subsequent transitions to simple cubic arsenic (c-As) and incommensurate host-guest arsenic (hg-As) phases at 25.9 and 44.8 GPa, respectively. Superconductivity emerges above 25 GPa in the c-As phase, with the superconducting transition temperature ($T$$\rm_c$) remaining nearly a constant of 3 K. Upon further compression, $T$$\rm_c$ steeply increases to a higher value around 4.5 K in the incommensurate hg-As phase above 43 GPa. We use our results to update the structural and superconducting phase diagrams under pressure for the novel semiconductor, black arsenic.

cond-mat.supr-con↗

arXiv2023

Cluster expansion by transfer learning for phase stability predictions

Recent progress towards universal machine-learned interatomic potentials holds considerable promise for materials discovery. Yet the accuracy of these potentials for predicting phase stability may still be limited. In contrast, cluster expansions provide accurate phase stability predictions but are computationally demanding to parameterize from first principles, especially for structures of low dimension or with a large number of components, such as interfaces or multimetal catalysts. We overcome this trade-off via transfer learning. Using Bayesian inference, we incorporate prior statistical knowledge from machine-learned and physics-based potentials, enabling us to sample the most informative configurations and to efficiently fit first-principles cluster expansions. This algorithm is tested on Pt:Ni, showing robust convergence of the mixing energies as a function of sample size with reduced statistical fluctuations.

cond-mat.mtrl-sci↗

arXiv2023

Pressure-induced superconductivity in the van der Waals semiconductor violet phosphorus

The van der Waals (vdW) semiconductor black phosphorus has been widely studied, especially after the discovery of phosphorene. On the contrary, its sister compound violet phosphorus, also a vdW semiconductor, has been rarely studied. Here we report the pressure-induced superconductivity in violet phosphorus up to $\sim$40 GPa. The superconductivity emerges at 2.75 GPa, which is well below the structural transition from monoclinic ($M$) to rhombohedral ($R$) structure at 8.5 GPa. The superconducting transition temperature ($T$$\rm_c$) shows a plateau of $\sim$7 K from 3.6 to 15 GPa, across the $M$ to $R$ structural transition, then jumps to another plateau of $\sim$10 K in the simple cubic ($C$) structure above 15 GPa. The temperature-pressure superconducting phase diagram of violet phosphorus is established, which is different from that of black phosphorus at low pressure. For black phosphorus, the superconductivity emerges until the structural transition from orthorhombic ($O$) to $R$ structure at $\sim$5 GPa, with a lower $T$$\rm_c$ than violet phosphorus. The pressure-induced superconductivity in violet phosphorus demonstrates its tunable electronic properties, and more electronics and optoelectronic applications are expected from this stable vdW semiconductor at ambient conditions.

cond-mat.supr-con↗