Ground State and Electronic Properties of Americium (Am) Compounds

2016 ◽  
Vol 1141 ◽  
pp. 176-179
Author(s):  
Jagdeesh Pataiya ◽  
Mahendra Aynyas ◽  
Chandrabhan Makode ◽  
Sankar P. Sanyal
Keyword(s):  
Electronic Properties ◽  
Ground State ◽  
Local Density ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Tight Binding ◽  
Type Structure ◽  
Cscl Type ◽  
Lmto Method ◽  
First Time

The ground state and electronic properties of americium pnictides (AmY, Y=N, P) has been calculated with the help of tight binding linear muffin-in-orbital (TB-LMTO) method within the local density approximation (LDA). From present study it is found that AmN and AmP are stable in NaCl – type structure under ambient pressure. The structural stability of AmN and AmP changes under the application of pressure. We predict a structural phase transition from NaCl-type to CsCl-type structure for these Am-pnictides in the pressure range of 36.0 – 47.0 GPa (AmN-AmP). Optimized lattice parameters, transition pressures and bulk modulus were obtained for the first time and analyzed in comparison with the available theoretical and experimental data.

Structural and Electronic Properties of Thulium Compounds

2016 ◽  
Vol 28 ◽  
pp. 59-64
Author(s):  
Yeshvir Singh Panwar ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Local Density ◽  
Structural Phase ◽  
Tight Binding ◽  
Energy Band Diagram ◽  
Lattice Parameter ◽  
Band Diagram ◽  
Cscl Type ◽  
Structural And Electronic Properties ◽  
Lmto Method

The tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA) is used to study the electronic structure and high pressure behaviour of thulium compounds TmX (X= P, As, S, and Se). We also predict a structural phase transition from NaCl to CsCl-type structure. The transition pressures were found to be 40.0, 31.0, 58.0 and 49.0 GPa, for TmP, TmAs, TmS and TmSe respectively. Apart from this, the lattice parameter (a0), bulk modulus (B0), band structure and density of states are calculated. From energy band diagram, it is observed that these compounds exhibit weak metallic character. The calculated values of lattice parameters and bulk modulus are of reasonable agreement with available data.

scholarly journals First Principles Study of Electronic Structure and Magnetic Properties of TMH (TM = Cr, Mn, Fe, Co)

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
S. Kanagaprabha ◽  
R. Rajeswarapalanichamy ◽  
K. Iyakutti
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Local Density ◽  
Hexagonal Phase ◽  
Structural Phase ◽  
Tight Binding ◽  
Transition Metal Hydrides ◽  
Lmto Method

First principles calculations are performed using a tight-binding linear muffin-tin orbital (TB-LMTO) method with local density approximation (LDA) and atomic sphere approximation (ASA) to understand the electronic properties of transition metal hydrides (TMH) (TM = Cr, Mn, Fe, Co). The structural property, electronic structure, and magnetic properties are investigated. A pressure induced structural phase transition from cubic to hexagonal phase is predicted at the pressures of 50 GPa for CrH and 23 GPa for CoH. Also, magnetic phase transition is observed in FeH and CoH at the pressures of 10 GPa and 180 GPa, respectively.

First Principle Calculations of Pressure Induced Structural and Electronic Properties in Americium Monochalcogenides

2014 ◽  
Vol 1047 ◽  
pp. 35-40 ◽  
Author(s):  
Jagdeesh Pataiya ◽  
Mahendra Aynyas ◽  
Chandrabhan Makode ◽  
Archana Singh ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Energy Band ◽  
Phase Structure ◽  
Local Density ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Tight Binding ◽  
Theoretical Data ◽  
Lattice Parameters ◽  
Type B

The tight-binding linear muffin-tin orbital (TB-LMTO) with in the local density approximation is used to calculate total energy, lattice parameters, bulk modulus, density of states and energy band structures of americium monochalcogenides at ambient as well as high pressure. It is found that AmX (X=S, Se, Te) compounds are stable in NaCl – type structure under ambient pressure. We predict a structural phase transition from NaCl-type (B1-phase) structure to CsCl-type (B2-phase) structure for these compounds in the pressure range of 26.0 – 15.0 GPa (AmS to AmTe). From energy band diagram it is observed that AmX compounds exhibit metallic behaviour. The calculated ground state properties such as lattice parameters and bulk modulus are in general good agreement with available experimental and theoretical data.

Ab Initio Study of Pressure Induced Structural, Magnetic and Electronic Properties in Plutonium Pnictides

2014 ◽  
Vol 1047 ◽  
pp. 11-17 ◽  
Author(s):  
Chandrabhan Makode ◽  
Jagdeesh Pataiya ◽  
M. Aynyas ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Total Energy ◽  
Electronic Properties ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Tight Binding ◽  
Energy Band Diagram ◽  
Lattice Parameter ◽  
Local Spin Density Approximation ◽  
Type B

We have investigated the pressure induced structural and electronic properties of plutonium pnictides (PuY, Y= P, As, Sb). The total energy as a function of volume is obtained by means of self-consistent tight binding linear muffin-in-orbital (TB-LMTO) method within the local spin density approximation (LSDA). From present study with the help of total energy calculations (spin polarized) it is found that PuP, PuAs and PuSb are stable in NaCl – type structure under ambient pressure. The structural stability of PuP, PuAs and PuSb changes under the application of pressure. We predict a structural phase transition from NaCl-type (B1-phase) to CsCl-type (B2-phase) structure for these Pu-pnictides in the pressure range of 20.8 – 42.0 GPa. We also calculate the lattice parameter, bulk modulus, band structure and density of states. From energy band diagram it is observed that all the three compounds exhibit metallic behaviour. The calculated equilibrium lattice parameters and bulk modulus are in good agreement with available experimental data.

Pressure Induced Structural and Electronic Properties of Thulium Nitride

2014 ◽  
Vol 1047 ◽  
pp. 147-150
Author(s):  
Yeshvir Singh Panwar ◽  
Mahendra Aynyas ◽  
M.K. Tejraj ◽  
S.P. Sanyal
Keyword(s):  
Phase Transition ◽  
Bulk Modulus ◽  
Electronic Properties ◽  
Structural Phase Transition ◽  
Phase Structure ◽  
Local Density ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Lattice Parameter ◽  
Type B

We report ab initio calculations of pressure induced structural phase transition and electronic properties of thulium nitride (TmN). The total energy as a function of volume is obtained by using the self-consistent tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA). It is found that TmN is stable in NaCl – type structure under ambient pressure. We predict a structural phase transition from NaCl-type (B1-phase) structure to CsCl-type (B2-phase) structure of this compound at a high pressure of 68 GPa. We also calculate the lattice parameter (a0), bulk modulus (B0), band structure and density of states. From energy band diagram it is observed that TmN exhibit metallic behaviour. The calculated values of equilibrium lattice parameter and bulk modulus are in general good agreement with available experimental data.

scholarly journals Electronic and structural properties of rare earth pnictides

2016 ◽  
Vol 34 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Ramakant Bhardwaj
Keyword(s):  
Rare Earth ◽  
Electronic Band Structure ◽  
Local Density ◽  
Structural Parameters ◽  
Structural Phase ◽  
Tight Binding ◽  
Lattice Parameter ◽  
Type Structure ◽  
Present Calculation ◽  
Electronic Band

AbstractIn the present paper structural and electronic properties of rare earth pnictides have been presented. The present calculation has been performed using self-consistent tight binding linear muffin tin orbital (TB-LMTO) method within the local density approximation (LDA). The studied compounds undergo a structural phase transition from NaCl-type structure to CsCl-type structure. The electronic band structure and density of states of the pnictides have been reported. The equilibrium lattice parameter a (Å), bulk modulus B (GPa), number of f-states at the Fermi level Nf (states/Ry cell) and volume collapse of AmBi and CmBi have also been reported. The calculated equilibrium structural parameters are in good agreement with the available experimental results.

Ab Initio Electronic Band Structure Calculations for Calcium Monochalcogenides

1998 ◽  
Vol 12 (16n17) ◽  
pp. 1709-1717 ◽  
Author(s):  
I. B. Shameem Banu ◽  
G. Kalpana ◽  
B. Palanivel ◽  
P. Shenbagaraman ◽  
M. Rajagopalan ◽  
...  
Keyword(s):  
Band Gap ◽  
Ground State ◽  
Energy Gap ◽  
Structural Phase ◽  
Type Structure ◽  
Band Structures ◽  
Electronic Band ◽  
Ground State Properties ◽  
Cscl Type ◽  
Total Energies

The first principles tight-binding linear muffin-tin orbital method within the local density approximation was used to calculate the electronic band structures and the total energies of CaS, CaSe and CaTe in NaCl-type and CsCl-type structures. The total energies were used to calculate the ground state properties such as lattice parameter, bulk modulus and the structural phase stability of these compounds. The transition pressure at which these compounds undergo the structural phase transition from NaCl-type to CsCl-type structure were calculated. The ground state properties, the transition pressures and the transition volumes are found to agree with the experimental and other theoretical results. The energy band gap at ambient condition in the NaCl-type structure were calculated and compared with the experimental results available for CaS and CaSe. For CaTe the experimental values of energy gap are not available. The valence-band width and the pressure coefficient of energy gap were also calculated. The closure of band gap at transition in CsCl structure for CaSe, and CaTe were explained by comparing the band structures of BaSe and SrSe in this phase.

Ab Initio Study of Structural Phase Transition and Electronic Properties in Samarium (Sm) Compounds

2016 ◽  
Vol 1141 ◽  
pp. 184-189
Author(s):  
Yeshvir Singh Panwar ◽  
Mahendra Aynyas ◽  
Jagdeesh Pataiya ◽  
Sankar P. Sanyal
Keyword(s):  
Phase Transition ◽  
Bulk Modulus ◽  
Structural Phase Transition ◽  
Local Density ◽  
Structural Phase ◽  
Tight Binding ◽  
Energy Band Diagram ◽  
Lattice Parameter ◽  
Type B ◽  
Lmto Method

The electronic structure and high pressure structural phase transition of SmTe and SmPo have been studied by using tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA). The total energy as a function of volume is obtained and it is found that these compounds are stable in NaCl-type (B1-phase) structure and transform to CsCl-type (B2-type) structure. The transition pressure of SmTe and SmPo are found to be 6.6 GPa and 8.6 GPa respectively. We have also calculated lattice parameter (a0), bulk modulus (B0), band structure (BS) and density of states (DOS). From energy band diagram, we observed that these compounds exhibit weakly metallic behaviour. The calculated values of lattice parameter and bulk modulus agree well with the available data.

scholarly journals High-pressure study of binary thorium compounds from first principles theory and comparisons with experiment

2014 ◽  
Vol 70 (3) ◽  
pp. 459-468 ◽  
Author(s):  
V. Kanchana ◽  
G. Vaitheeswaran ◽  
A. Svane ◽  
S. Heathman ◽  
L. Gerward ◽  
...  
Keyword(s):  
High Pressure ◽  
Equations Of State ◽  
Structural Phase ◽  
Experimental Results ◽  
Full Potential ◽  
Generalized Gradient ◽  
Structural Behaviour ◽  
Cscl Type ◽  
Lmto Method ◽  
Thorium Compounds

The high-pressure structural behaviour of a series of binary thorium compounds ThX(X= C, N, P, As, Sb, Bi, S, Se, Te) is studied using the all-electron full potential linear muffin-tin orbital (FP-LMTO) method within the generalized gradient approximation (GGA) for the exchange and correlation potential. The calculated equlibrium lattice parameters and bulk moduli, as well as the equations of state agree well with experimental results. New experiments are reported for ThBi and ThN. Calculations are performed for the ThXcompounds in the NaCl- and CsCl-type crystal structures, and structural phase transitions from NaCl to CsCl are found in ThP, ThAs, ThSb and ThSe at pressures of 26.1, 22.1, 8.1 and 23.2 GPa, respectively, in excellent agreement with experimental results. ThC, ThN and ThS are found to be stable in the NaCl structure, and ThBi and ThTe in the CsCl structure, for pressures below 50 GPa. The electronic structures of the ThXcompounds are studied using the quasiparticle self-consistentGWmethod (G: Green function,W: dynamically screened interaction).

INSULATOR-TO-METAL TRANSITION IN LaRhO3 UNDER HIGH PRESSURE

1995 ◽  
Vol 09 (11n12) ◽  
pp. 701-709 ◽  
Author(s):  
R. ASOKAMANI ◽  
CH. U.M. TRINADH ◽  
G. PARI ◽  
S. NATARAJAN
Keyword(s):  
High Pressures ◽  
Local Density ◽  
Tight Binding ◽  
Band Structure Calculations ◽  
Equilibrium Lattice Constant ◽  
Band Insulator ◽  
Lmto Method ◽  
A Charge ◽  
Structure Calculations ◽  
Cell Volumes

The band structure calculations of perovskite transition metal compound LaRhO 3 performed using 'tight binding linear muffin tin orbital' (TB-LMTO) method within local density approximation (LDA) under ambient and high pressures are reported here. Our calculations are able to successfully explain the insulating nature of the system and the insulator-to-metal transition (IMT) is observed for the reduced volume of 0.90. The first electronic structure calculation reported here for LaRhO 3 enables us to compare it with that of LaCoO 3 which brings out the role played by the d bands. These studies lead to distinguish between these two insulating systems and LaCoO 3 is found to be a charge transfer (CT) insulator which is in agreement with the recent experimental observations whereas LaRhO 3 is a conventional band insulator. Further, the equilibrium lattice constant, bulk modulus, its first derivative, and metallization volume obtained from the total energy calculations for expanded and reduced cell volumes are also reported for LaRhO 3.

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