First-Principles Investigation of Spin-Phonon Coupling in Vanadium-Based Molecular Spin Quantum Bits
First-Principles Investigation of Spin-Phonon Coupling in Vanadium-Based Molecular Spin Quantum Bits
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DOI：
10.1021/acs.inorgchem.9b01407
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发表时间：
2019-08-05
影响因子：
4.6
通讯作者：
Lunghi, Alessandro
中科院分区：
文献类型：
--
作者：
Albino, Andrea;Benci, Stefano;Lunghi, Alessandro
顺磁性分子可以显示出很长的自旋相干时间，这使它们成为量子比特（qubit）的良好候选者。降低自旋-声子相互作用的效率是在软分子晶格中在宽温度范围内实现长相干时间的主要挑战。缺乏对振动在自旋弛豫中的作用的微观理解，强烈破坏了化学设计性能更好的分子量子比特的可能性。在这里，我们报告的第一性原理表征的主要机制，有助于自旋-声子耦合的一类钒（IV）分子量子比特。后Hartree-Fock和密度泛函理论方法被用来确定两个分子间和分子内振动的塞曼能量的调制的效果，显示出不同的配位几何形状和配体的四个分子。这项比较研究提供了第一个洞察所发挥的作用，由配位几何形状和配位场强度在确定自旋晶格弛豫时间的分子量子比特，开辟了一条途径，以合理设计新的化合物。
Paramagnetic molecules can show long spin-coherence times, which make them good candidates as quantum bits (qubits). Reducing the efficiency of the spin-phonon interaction is the primary challenge toward achieving long coherence times over a wide temperature range in soft molecular lattices. The lack of a microscopic understanding about the role of vibrations in spin relaxation strongly undermines the possibility of chemically designing better-performing molecular qubits. Here we report a first-principles characterization of the main mechanism contributing to the spin-phonon coupling for a class of vanadium(IV) molecular qubits. Post-Hartree-Fock and density functional theory methods are used to determine the effect of both intermolecular and intramolecular vibrations on modulation of the Zeeman energy for four molecules showing different coordination geometries and ligands. This comparative study provides the first insight into the role played by coordination geometry and ligand-field strength in determining the spin- lattice relaxation time of molecular qubits, opening an avenue to the rational design of new compounds.