（Ga，Mn）N纳米晶中反铁磁有序的密度泛函理论研究

Paraelectric KH$_2$PO$_4$ Nanocrystals in Monolithic Mesoporous Silica: Structure and Lattice Dynamics

Combining dielectric crystals with mesoporous solids allows a versatile design of functional nanomaterials, where the porous host provides a mechanical rigid scaffold structure and the molecular filling adds the functionalization. Here, we report a study of the complex lattice dynamics of a SiO$_2$:KH$_2$PO$_4$ nanocomposite consisting of a monolithic, mesoporous silica glass host with KH$_2$PO$_4$ nanocrystals embedded in its tubular channels $\sim$12 nm across. A micro-Raman investigation performed in the spectral range of 70-1600 cm$^{-1}$ reveals the complex lattice dynamics of the confine…

稳定的反铁磁石墨烯

Stable antiferromagnetic graphone

采用密度泛函方法模拟了氢原子和氟原子吸附在单面单亚晶格功能化石墨烯（graphone）上的原子结构，并计算了其电子结构.结果表明，氟的功能化不仅提高了化合物的稳定性，而且提供了磁性基态从铁磁性到反铁磁性的转换。对氟基石墨烯中的半金属铁磁态进行了讨论。

一维YIG孔基磁子纳米晶体

1D YIG hole-based magnonic nanocrystal

本文报道了一种一维YIG磁子晶体的设计、制备与表征，通过纳米孔结构实现超过5微米的磁子波传输，并发现显著的带隙效应。

单分子磁体Mn12与铁磁衬底的反铁磁耦合

Antiferromagnetic coupling of the single-molecule magnet Mn12 to a ferromagnetic substrate

利用密度泛函理论和DFT+U方法研究了单层原型单分子磁体Mn 12和铁磁Ni（111）衬底之间通过S的磁耦合.我们的DFT和DFT+U计算表明，Mn 12分子有利于反铁磁耦合到Ni衬底，他们拥有的磁矩偏离孤立的Mn 12分子的磁矩。我们发现，Mn 12在Ni（整个系统）上的易磁化轴是由Ni衬底的。反铁磁耦合主要是由Mn和Ni基体之间的磁矩通过S、C和O阴离子的超交换相互作用引起的。我们的发现可以通过X射线磁性圆二色性或扫描隧道显微镜观察到。

Part of a collection of reviews on antiferromagnetic spintronics. Antiferromagnetic dynamics, spin-texures, and nanostructures

Antiferromagnets as active elements of spintronics can be faster than their ferromagnetic counterparts and more robust to magnetic noise. Owing to the strongly exchange-coupled magnetic sublattice structure, antiferromagnetic order parameter dynamics are qualitatively different and thus capable of engendering novel device functionalities. In this review, we discuss antiferromagnetic textures -- nanoparticles, domain walls, and skyrmions, -- under the action of different spin torques. We contrast the antiferromagnetic and ferromagnetic dynamics, with a focus on the features that can be relevant…

Electronic structure of semiconductor nanoparticles from stochastic evaluation of imaginary-time path integral

In the Kohn-Sham orbital basis imaginary-time path integral for electrons in a semiconductor nanoparticle has a mild Fermion sign problem and is amenable to evaluation by the standard stochastic methods. This is evidenced by the simulations of silicon hydrogen-passivated nanocrystals, such as $Si_{35}H_{36},~Si_{87}H_{76},~Si_{147}H_{100}$ and $Si_{293}H_{172},$ which contain $176$ to $1344$ valence electrons and range in size $1.0 - 2.4~nm$, utilizing the output of density functional theory simulations. We find that approximating Fermion action with just the leading order polarization term re…

Topological energy release from collision of relativistic antiferromagnetic solitons

Magnetic solitons offer functionalities as information carriers in multiple spintronic and magnonic applications. However, their potential for nanoscale energy transport has not been revealed. Here we demonstrate that antiferromagnetic solitons, e.g. domain walls, can uptake, transport and release energy. The key for this functionality resides in their relativistic kinematics; their self-energy increases with velocity due to Lorentz contraction of the soliton and their dynamics can be accelerated up to the effective speed of light of the magnetic medium. Furthermore, their classification in ro…

Transport Spin Polarization of Noncollinear Antiferromagnetic Antiperovskites

Spin-polarized currents play a key role in spintronics. Recently, it has been found that antiferromagnets with a non-spin-degenerate band structure can efficiently spin-polarize electric currents, even though their net magnetization is zero. Among the antiferromagnetic metals with magnetic space group symmetry supporting this functionality, the noncollinear antiferromagnetic antiperovskites ANMn$_3$ (A = Ga, Ni, Sn, and Pt) are especially promising. This is due to their high Néel temperatures and a good lattice match to perovskite oxide substrates, offering possibilities of high structural qua…

Antiferromagnetic critical point on graphene's honeycomb lattice: A functional renormalization group approach

Electrons on the half-filled honeycomb lattice are expected to undergo a direct continuous transition from the semimetallic into the antiferromagnetic insulating phase with increase of on-site Hubbard repulsion. We attempt to further quantify the critical behavior at this quantum phase transition by means of functional renormalization group (RG), within an effective Gross-Neveu-Yukawa theory for an SO(3) order parameter ("chiral Heisenberg universality class"). Our calculation yields an estimate of the critical exponents $ν\simeq 1.31$, $η_ϕ\simeq 1.01$, and $η_Ψ\simeq 0.08$, in reasonable agr…

双层石墨烯中层反铁磁态的第一性原理研究

Layer Antiferromagnetic State in Bilayer Graphene : A First-Principle Investigation

采用局域自旋密度近似的密度泛函方法研究了双层石墨烯的基态。我们发现了一个层反铁磁有序的基态，这是前人基于简化模型的研究所提出的。计算结果表明，即使考虑到远距离跳跃和非局域库仑相互作用，层反铁磁态（LAF）仍是稳定的。LAF态的能隙约为1.8 meV，与实验值相当。BLG的表面磁性为$10^{-2} μ_B /nm^2 $量级。

Sublinear scaling for time-dependent stochastic density functional theory

A stochastic approach to time-dependent density functional theory (TDDFT) is developed for computing the absorption cross section and the random phase approximation (RPA) correlation energy. The core idea of the approach involves time-propagation of a small set of stochastic orbitals which are first projected on the occupied space and then propagated in time according to the time-dependent Kohn-Sham equations. The evolving electron density is exactly represented when the number of random orbitals is infinite, but even a small number (? 16) of such orbitals is enough to obtain meaningful result…

Stochastic Optimally-Tuned Ranged-Separated Hybrid Density Functional Theory

We develop a stochastic formulation of the optimally-tuned range-separated hybrid density functional theory which enables significant reduction of the computational effort and scaling of the non-local exchange operator at the price of introducing a controllable statistical error. Our method is based on stochastic representations of the Coulomb convolution integral and of the generalized Kohn-Sham density matrix. The computational cost of the approach is similar to that of usual Kohn-Sham density functional theory, yet it provides much more accurate description of the quasiparticle energies for…