A computational study on a multimode spin conductance switching by coordination isomerization in organometallic single-molecule junctions

Abstract

Single-molecule junctions provide the additional flexibility of tuning the on/off conductance states through molecular design. Here, we focus on a family of organometallic complexes with a conjugated curved buckybowl as the ligand. Using first-principles calculations, a multi-mode reversible spin switching based on the CpFe·corannulene complex is predicted by the temperature control of the CpFe+ coordination position in corannulene. The different spin conductance states for three coordinated modes are ascribed to the different electronic spin states of the organometallic complex due to crystal field effects. The predicted relative stabilities of isomers and the energy barriers of isomerization reactions can ensure that the conversion among the three isomers can occur quickly and, at a specific temperature, a dominant isomer has a higher proportion than the other two isomers. This provides a new framework for understanding transport in organometallic complexes with localized d states. This presents an exciting opportunity for exploiting junctions involving molecular spin switching.

Conductance Switching in an Organometallic Single-Electron Transistor Using Current-Constrained Reduced-Density Matrix Theory

“…It must be emphasized that while orbital degeneracies in the low-bias Kondo regime for organometallics have been amply demonstrated in experiments 23,36−42 and understood theoretically, 43 analysis for organometallic based electrochemical switches is mostly restricted to the singlereferenced framework. 16,19,44,45 In this report we thus address this lacuna, and to the best of our knowledge, such a correlated treatment of the electrochemical switching action in organometallics is the first of its kind. Interestingly enough we shall see that even though uncorrelated methods would not capture the intrinsic details of the ground-state electronic structure of such systems well, such uncorrelated frameworks may still be used to reproduce qualitative trends in transport properties.…”

“…Two-particle reduced density matrix (2-RDM) , based electronic structure methods − have proven in the past to recover such significant nondynamic correlation in organometallics and its effect has been interpreted in a wide range of chemically relevant phenomena like the superexchange mechanism, dimerization, structure of metalloproteins, , redox events, , etc. It must be emphasized that while orbital degeneracies in the low-bias Kondo regime for organometallics have been amply demonstrated in experiments ,− and understood theoretically, analysis for organometallic based electrochemical switches is mostly restricted to the single-referenced framework. ,,, In this report we thus address this lacuna, and to the best of our knowledge, such a correlated treatment of the electrochemical switching action in organometallics is the first of its kind. Interestingly enough we shall see that even though uncorrelated methods would not capture the intrinsic details of the ground-state electronic structure of such systems well, such uncorrelated frameworks may still be used to reproduce qualitative trends in transport properties.…”

“…In recent years, organometallics have emerged as a versatile candidate for realizing the power of molecular conducting machines due to their functional diversification, , ease of tunability of molecular energy levels with respect to the Fermi level of bulk electrodes, , scalable replication by self-assembly, − and extension to multiple centers by synthetic tailorability. − In fact the redox activity of the metallic centers of such organometallic complexes can be manipulated externally to create robust molecular switches, which serve to perform logical operations. Indeed many such molecular switches using iron centers − and electrochemically controlled Os centers, Tb centers controlled using hyperfine interaction, and Ru or Mo centers controlled either electrically , or even by both optical and electrochemical stimuli have been implemented . The ability to perform such switching operations with single molecules will emerge as a viable alternative as below a certain miniaturization, conventional silicon-based chips suffer from the unavoidable nuisance of leakage current which hinders maintaining a high ON/OFF current ratio, thereby posing as a fundamental limit to its operational quality.…”

Computational study on new natural compound agonists of dopamine receptor

“…So, these two selected compounds might have higher affinity and stability when binding with DAR than Bromocriptine. Structures of ligands and DAR were also analyzed, including hydrogen bonds, Pi-Pi interaction, Alkyl interaction and Pi-Alkyl interaction [24]. As shown in Figures 2, 3 and Tables 5, 6, compound 1 and compound 2 didn't form any Pi-Pi interaction, Alkyl interaction and Pi-Alkyl interaction.…”

Perfect Spin Filtering in Homobimetallic Ni Complex with High Tolerance to Structural Changes

“…To meet the increasingly urgent demand for miniaturization of microelectronic devices and their further functionalization, individual molecules with the great potential of molecular electronics have attracted unprecedented interest in recent years arising from their diverse structures, good self-assembly ability, intrinsic quantum mechanical behavior, the ease of energy gap tuning, etc. − To this end, materials with stable and perfect spin filtering transport possess huge application potential in information storage and molecular spin conductance switches. − With the development of spintronics, high and stable spin filtering efficiency of molecular devices has become one of the major challenges. − Splitting and electronic arrangement of the central metal d-orbitals determines the spin states of transition-metal complexes, which depend on the ratio between the ligand field energy, E LF , and the spin exchange energy, E EXC. Spin crossover (SCO) − complexes including 3d 4 –3d 7 transition metals are the most investigated ones.…”