Molecular electronic spins represent one of the most promising building blocks for the design of quantum computing architectures. However, the advancement of this technology requires the increase of spin lifetime at ambient temperature. Spin-phonon coupling has been recognized as the key interaction dictating spin relaxation at high temperature in molecular crystals and the search for chemical-design principles to control such interaction are a fundamental challenge in the field. Here we present a multi-reference first-principles analysis of the g-tensor and the spin-phonon coupling in a series of four exa-coordinate Vanadium(IV) molecular complexes, where the catecholate ligand donor atom is progressively changed from Oxygen to Sulphur, Selenium and Tellurium. A ligand field interpretation of the multi-reference electronic structure theory results made it possible to rationalize the correlation between the molecular g-shifts and the average spin-phonon coupling coefficients, revealing the role of spin-orbit coupling, chemical bond covalency and energy splitting of d-like orbitals in spin relaxation. Our study reveals the simultaneous increase of metal-ligand covalency and electronic excited state energy separation as key elements of an optimal strategy towards long spin-lattice lifetimes in molecular qubits.
Ligand-Controlled Phonon Dynamics in CsPbBr3 Nanocrystals Revealed by Machine-Learned Interatomic Potentials
Georgia Institute of Technology（佐治亚理工学院）；Queens College, City University of New York（纽约市立大学皇后学院）；The Graduate Center, City University of New York（纽约市立大学研究生中心）
Novel 2D Altermagnetic Vanadium Oxide with a Buckled Lieb Structure
UNAM - National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology, Bilkent University（比尔肯特大学纳米技术与材料科学研究所）；Linköping University（林雪平大学）；Uppsala University（乌普萨拉大学）；University of Iowa（爱荷华大学）
基于密度泛函理论第一性原理计算，发现单层V₂O晶体在翘曲Lieb晶格中是一种二维交变磁性材料，具有负泊松比、面外易磁化轴、1.2 eV动量依赖自旋劈裂以及大贝里曲率和约40 (ℏ/e) S cm⁻¹的自旋霍尔电导率。
Electronic correlations and fluctuating lattice distortions in vanadium dioxide
Collège de France, PSL Research University（法兰西学院，PSL研究大学）；Institute of Theoretical Physics, University of Hamburg（汉堡大学理论物理研究所）；The Hamburg Centre for Ultrafast Imaging（汉堡超快成像中心）；RWTH Aachen University（亚琛工业大学）；Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg（维尔茨堡大学理论物理与天体物理研究所及维尔茨堡-德累斯顿卓越集群ct.qmat）
Spin-lattice couplings in two-dimensional CrI$_3$ from first-principles study
由于热波动变得更加重要的尺寸缩小，预计低维磁体更敏感的晶格畸变和声子比体系统。在这里，我们提出了一个完整的相对论第一性原理研究的自旋晶格耦合，即如何磁相互作用依赖于局部晶格畸变，原型的二维铁磁体CrI $_3$。我们提取一个有效的措施的自旋-晶格耦合在铬$_3$这是高达十倍以上的bcc铁。磁交换相互作用，包括Heisenberg相互作用和相对论Dzyaloshinskiii-Moriya相互作用，对Cr原子的面内运动和配体原子的面外运动都很敏感。我们发现，显着的磁对相互作用的符号从铁磁（FM）反铁磁（AFM）原子位移大于0.16 <$。我们解释所观察到的强自旋晶格耦合通过分析各向同性交换相互作用的轨道分解，涉及不同的晶体场分裂铬$-3d$轨道。AFM t $_{2g}$ - t $_{2g}$和FM t $_{2g}$ - e $_{g}$贡献之间的竞争依赖于Cr和I原子形成的键角以及Cr-Cr距离。特别地，如果Cr原子被置换，则当I-Cr-I键角接近90 ° $^\circ$时，FM-AFM符号改变。所得到的自旋-晶格耦合常数，结合微观轨道分析，可作为进一步研究二维磁体热力学性质和磁振子-声子联合激发的指导原则。
Trigonal Distortion Driven Ground States in VX3 (X = Br and I)
University of Houston（休斯顿大学）；Helmholtz-Zentrum Berlin für Materialien und Energie（柏林亥姆霍兹材料与能源中心）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；National Synchrotron Radiation Research Center（国家同步辐射研究中心）
