arXiv subjects

Lan Li

Publications and source records attributed to Lan Li.

39 records · Page 3Linked to original sources

arXiv2013

Demonstration of mid-infrared waveguide photonic crystal cavities

We have demonstrated what we believe to be the first waveguide photonic crystal cavity operating in the mid-infrared. The devices were fabricated from Ge23Sb7S70 chalcogenide glass on CaF2 substrates by combing photolithographic patterning and focus ion beam milling. The waveguide-coupled cavities were characterized using a fiber end fire coupling method at 5.2 μm wavelength, and a loaded quality factor of ~ 2,000 was measured near the critical coupling regime.

physics.optics↗

arXiv2012

First-Principles Studies of the Atomic, Electronic, and Magnetic Structure of a-MnO2 (Cryptomelane)

Density functional theory calculations are used to investigate a-MnO2, a structure containing a framework of corner and edge sharing MnO6 octahedra with tunnels in between. Placing K+ ions into the tunnels stabilizes a-MnO2 with respect to the rutile-structure b-MnO2 phase, in agreement with experiment. The computed magnetic structure has antiferromagnetic (ferromagnetic) Mn-Mn interactions between corner-sharing (edge-sharing) octahedra. Pure a-MnO2 is found to be a semiconductor with an indirect band gap of 1.3 eV. Water and related hydrides (OH-; H3O+) can also be accommodated in the tunnels; the equilibrium K-O distance increases with increasing oxygen hydride charge.

cond-mat.mtrl-sci↗

arXiv2003

Scaling in directed dynamical small-world networks with random responses

A dynamical model of small-world network, with directed links which describe various correlations in social and natural phenomena, is presented. Random responses of every site to the imput message are introduced to simulate real systems. The interplay of these ingredients results in collective dynamical evolution of a spin-like variable S(t) of the whole network. In the present model, global average spreading length \langel L >_s and average spreading time _s are found to scale as p^-αln N with different exponents. Meanwhile, S behaves in a duple scaling form for N>>N^*: S ~ f(p^-βq^γt'_sc), where p and q are rewiring and external parameters, α, β, γand f(t'_sc) are scaling exponents and universal functions, respectively. Possible applications of the model are discussed.

cond-mat.dis-nn↗