Li Yong-Qing

Electrostatic field effects on three-dimensional topological insulators

Three-dimensional topological insulators are a new class of quantum matter which has interesting connections to nearly all main branches of condensed matter physics. In this article, we briefly review the advances in the field effect control of chemical potential in three-dimensional topological insulators. It is essential to the observation of many exotic quantum phenomena predicted to emerge from the topological insulators and their hybrid structures with other materials. We also describe various methods for probing the surface state transport. Some challenges in experimental study of electron transport in topological insulators will also be briefly discussed.

Further Study of Λ-Related Quantum Interference of Π-State Diatomic on Collision-Induced Rotational Energy Transfer*

In our previous theoretical studies [Meng-Tao Sun, Yong-Qing Lee, and Feng-Cai Ma, Chem. Phys. Lett. 371 (2003) 342], we have reported the quantum interference on collision-induced rotational energy transfer on CO (A 1Π, v = 3) with inert gases, which originates from the difference between the two Λ-related collision potential energy surfaces. The interference angle, which measures the degree of coherence, is presented in this paper. Based on the time-dependent first order Born approximation, taking into account the anisotropic Lennard–Jones interaction potentials, the relation of the interference angle with the factors, including experimental temperature, partner, and rotational quantum number, are obtained. The changing tendencies with them are discussed. This theoretical model is important to understanding and performing this kind of experiment.

Simple formula for the ionization rate of diatomic molecules in an intense laser field using the velocity gauge

We derive a general ionization rate formula for the system of diatomic molecules in the velocity gauge. A more concise expression of the photoionization rate in the tunnel region is obtained for the first time. Comparisons are made among the different versions of strong-field approximation. The numerical study shows that the ionization rate in the velocity gauge is underestimated by a few orders compared with that in the length gauge. Our simple formula of ionization rate may provide an insight into the ionization mechanism for the system of diatomic molecules.

Relationship Between Differential Interference Angle and Parameter of Experiment in Molecular Beam

Collisional quantum interference (CQI) was observed in the intramolecular rotational energy transfer in the experiment of the static cell, and the integral interference angles were measured. To observe more precise information, the experiment in the molecular beam should be taken, from which the relationship between the differential interference angle and the scattering angle can be obtained. In this paper, the theoretical model of CQI is described in an atom-diatom system in the condition of the molecular beam, based on the first-Born approximation of time-dependent perturbation theory, taking into accounts the long-range interaction potential. The method of observing and measuring correctly the differential interference angle is presented. The changing tendency of the differential interference angle with the impact parameter and relative velocity is discussed. The changing tendencies of the differential interference angle with the parameter of experiment in the molecular beam, including the impact parameter and the velocity are discussed. This theoretical model is important to understand or perform the experiment in the molecular beam.

Spin correlations and colossal magnetoresistance in HgCr2Se4

This study aims to unravel the mechanism of colossal magnetoresistance (CMR) observed in

Vector correlations study of the reaction N(2D)+H2(X1Σg+)→NH(a1Δ)+H(2S) with different collision energies and reagent vibration excitations*

n\text{\ensuremath{-}}\mathrm{type} {\mathrm{HgCr}}_{2}{\mathrm{Se}}_{4}

Accurate equilibrium inversion barrier of ammonia by extrapolation to the one-electron basis set limit

, in which low-density conduction electrons are exchange-coupled to a three-dimensional Heisenberg ferromagnet with a Curie temperature

Excited State Properties of Fluorine-Substituted Hexabenzocoronene: A Quantum-Chemical Characterization

{T}_{C}\ensuremath{\approx}105

Collisional quantum interference on rotational energy transfer: physical interpretation of the differential interference angle

K. Near room temperature the electron transport exhibits an ordinary semiconducting behavior. As temperature drops below

Stereodynamics of the reactions: F + H2/HD/HT→FH + H/D/T*

{T}^{*}\ensuremath{\simeq}2.1{T}_{C}