Controlled spin-state switching in small molecules is of great interest for recent molecular spin... more Controlled spin-state switching in small molecules is of great interest for recent molecular spintronic and spin-caloritronic applications. The 3d transition metal incorporated porphyrin molecules with stable paramagnetic states are one of the most explored classes of molecules for this purpose where adsorption and desorption of small gaseous molecules (e.g., CO, NO, O2) on the transition metal center show efficient control over the spin states of metalloporphyrins. However, in the present study, using on-site Coulomb interaction incorporated density functional theory (DFT + U), we demonstrate reversible spin-state switching of NO-adsorbed manganese porphyrin (MnP) on top of a gold (111) surface by inducing conformational change in the molecular geometry. In this approach, mechanical manipulation by a scanning tunneling microscope (STM) tip can reversibly interchange the binding mode of the Mn–NO bond between ground-state linear and metastable bent conformations. And this modification leads to spin-state ...
Using ab initio molecular dynamics (AIMD) simulations, we have explored the structural reconstruc... more Using ab initio molecular dynamics (AIMD) simulations, we have explored the structural reconstruction of a special kind of line defect, which is constructed from tetragonal rings and is implanted at the heterojunction of hybrid boron nitride–graphene (BN–C) nanoribbons. It appears that nanoribbons get reconstructed in various ways to form different kinds of line defect depending upon the nature of the atoms at the heterojunction. Along with 5–8–5, we also report two new kinds of line defects, 8–8–8 and 7–4–7, at the heterojunction. The electronic and magnetic properties of the reconstructed nanoribbons are calculated using density functional theory (DFT). These nanoribbons show a wide range of electronic structures ranging from semiconducting to spin polarized metallic behaviour.
Abstract Using density functional theory we present a systematic study of the electronic and magn... more Abstract Using density functional theory we present a systematic study of the electronic and magnetic properties of various nickel clusters and two small bime-tallic clusters, NinCom and NinFem (n ? m B 6). A detail study of binding energy, magnetic moment and stability function of ...
Using ab-initio numerical methods, we explore the spin-dependent transport and thermoelectric pro... more Using ab-initio numerical methods, we explore the spin-dependent transport and thermoelectric properties of a spin-crossover molecule (i.e., iron complex of 2-(1H-pyrazol-1-yl)-6-(1H-tetrazole-5-yl)pyridine) based nano-junction. We demonstrate a large magnetoresistance, efficient conductance-switching, and spin-filter activity in this molecule-based two-terminal device. The spin-crossover process also modulates the thermoelectric entities. It can efficiently switch the magnitude as well as spin-polarization of the thermocurrent. We find that thermocurrent is changed by ∼4 orders of magnitude upon spin-crossover. Moreover, it also substantially affects the thermopower and consequently, the device shows extremely efficient spin-crossover magnetothermopower generation. Furthermore, by tuning the chemical potential of electrodes into a certain range, a pure spin-thermopower can be achieved for the high-spin state. Finally, the reasonably large values of figure-of-merit in the presence and absence of phonon demonstrate a large heat-to-voltage conversion efficiency of the device. We believe that our study will pave an alternative way of tuning the transport and thermoelectric properties through the spin-crossover process and can have potential applications in generation of spin-dependent current, information storage, and processing.
ABSTRACT Using constant-temperature ab initio molecular dynamics simulation we demonstrated a way... more ABSTRACT Using constant-temperature ab initio molecular dynamics simulation we demonstrated a way to insert extended line defects (ELDs) at the grain boundary in hybrid graphene and boron nitride nanoribbons (BNCNRs) as well as in pure graphene nanoribbons (GNRs) and pure boron nitride nanoribbons (BNNRs). Our systematic studies have shown that 5-8-5 and 8-8-8 extended line defects can be installed and stabilized by depositing different adatoms such as carbon, boron, and nitrogen at the grain boundaries of graphene–graphene, boron nitride–boron nitride, and graphene–boron nitride junctions. The electronic and magnetic structures of these nanoribbons are highly modulated in the presence of these ELDs.
Using the quantum master equation for many-body Hamiltonian, this study computationally investiga... more Using the quantum master equation for many-body Hamiltonian, this study computationally investigates highly non-linear current–voltage characteristics such as negative differential conductance, and Coulomb blockade in a small molecular bridge.
Controlled spin-state switching in small molecules is of great interest for recent molecular spin... more Controlled spin-state switching in small molecules is of great interest for recent molecular spintronic and spin-caloritronic applications. The 3d transition metal incorporated porphyrin molecules with stable paramagnetic states are one of the most explored classes of molecules for this purpose where adsorption and desorption of small gaseous molecules (e.g., CO, NO, O2) on the transition metal center show efficient control over the spin states of metalloporphyrins. However, in the present study, using on-site Coulomb interaction incorporated density functional theory (DFT + U), we demonstrate reversible spin-state switching of NO-adsorbed manganese porphyrin (MnP) on top of a gold (111) surface by inducing conformational change in the molecular geometry. In this approach, mechanical manipulation by a scanning tunneling microscope (STM) tip can reversibly interchange the binding mode of the Mn–NO bond between ground-state linear and metastable bent conformations. And this modification leads to spin-state ...
Using ab initio molecular dynamics (AIMD) simulations, we have explored the structural reconstruc... more Using ab initio molecular dynamics (AIMD) simulations, we have explored the structural reconstruction of a special kind of line defect, which is constructed from tetragonal rings and is implanted at the heterojunction of hybrid boron nitride–graphene (BN–C) nanoribbons. It appears that nanoribbons get reconstructed in various ways to form different kinds of line defect depending upon the nature of the atoms at the heterojunction. Along with 5–8–5, we also report two new kinds of line defects, 8–8–8 and 7–4–7, at the heterojunction. The electronic and magnetic properties of the reconstructed nanoribbons are calculated using density functional theory (DFT). These nanoribbons show a wide range of electronic structures ranging from semiconducting to spin polarized metallic behaviour.
Abstract Using density functional theory we present a systematic study of the electronic and magn... more Abstract Using density functional theory we present a systematic study of the electronic and magnetic properties of various nickel clusters and two small bime-tallic clusters, NinCom and NinFem (n ? m B 6). A detail study of binding energy, magnetic moment and stability function of ...
Using ab-initio numerical methods, we explore the spin-dependent transport and thermoelectric pro... more Using ab-initio numerical methods, we explore the spin-dependent transport and thermoelectric properties of a spin-crossover molecule (i.e., iron complex of 2-(1H-pyrazol-1-yl)-6-(1H-tetrazole-5-yl)pyridine) based nano-junction. We demonstrate a large magnetoresistance, efficient conductance-switching, and spin-filter activity in this molecule-based two-terminal device. The spin-crossover process also modulates the thermoelectric entities. It can efficiently switch the magnitude as well as spin-polarization of the thermocurrent. We find that thermocurrent is changed by ∼4 orders of magnitude upon spin-crossover. Moreover, it also substantially affects the thermopower and consequently, the device shows extremely efficient spin-crossover magnetothermopower generation. Furthermore, by tuning the chemical potential of electrodes into a certain range, a pure spin-thermopower can be achieved for the high-spin state. Finally, the reasonably large values of figure-of-merit in the presence and absence of phonon demonstrate a large heat-to-voltage conversion efficiency of the device. We believe that our study will pave an alternative way of tuning the transport and thermoelectric properties through the spin-crossover process and can have potential applications in generation of spin-dependent current, information storage, and processing.
ABSTRACT Using constant-temperature ab initio molecular dynamics simulation we demonstrated a way... more ABSTRACT Using constant-temperature ab initio molecular dynamics simulation we demonstrated a way to insert extended line defects (ELDs) at the grain boundary in hybrid graphene and boron nitride nanoribbons (BNCNRs) as well as in pure graphene nanoribbons (GNRs) and pure boron nitride nanoribbons (BNNRs). Our systematic studies have shown that 5-8-5 and 8-8-8 extended line defects can be installed and stabilized by depositing different adatoms such as carbon, boron, and nitrogen at the grain boundaries of graphene–graphene, boron nitride–boron nitride, and graphene–boron nitride junctions. The electronic and magnetic structures of these nanoribbons are highly modulated in the presence of these ELDs.
Using the quantum master equation for many-body Hamiltonian, this study computationally investiga... more Using the quantum master equation for many-body Hamiltonian, this study computationally investigates highly non-linear current–voltage characteristics such as negative differential conductance, and Coulomb blockade in a small molecular bridge.
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Papers by Prakash Parida