Perturbation expansion of the antiferromagnetic ground state

1973 ◽  
Vol 6 (4) ◽  
pp. 138-142 ◽  
Author(s):  
M. Parrinello ◽  
M. Scirè ◽  
T. Arai
Keyword(s):  
Ground State ◽  
Perturbation Expansion ◽  
Antiferromagnetic Ground State

scholarly journals First principles calculations of the structural, electronic, magnetic, and thermodynamic properties of the Nd2MgGe2 and Gd2MgGe2 intermetallic compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Menouer ◽  
O. Miloud Abid ◽  
A. Benzair ◽  
A. Yakoubi ◽  
H. Khachai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermodynamic Properties ◽  
Ground State ◽  
First Principles ◽  
Essential Role ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Rare Earth Compounds ◽  
First Principles Calculations ◽  
Antiferromagnetic Ground State

AbstractIn recent years the intermetallic ternary RE2MgGe2 (RE = rare earth) compounds attract interest in a variety of technological areas. We therefore investigate in the present work the structural, electronic, magnetic, and thermodynamic properties of Nd2MgGe2 and Gd2MgGe2. Spin–orbit coupling is found to play an essential role in realizing the antiferromagnetic ground state observed in experiments. Both materials show metallicity and application of a Debye-Slater model demonstrates low thermal conductivity and little effects of the RE atom on the thermodynamic behavior.

HIGH FIELD PHASE DIAGRAM OF THE FIELD-INDUCED SUPERCONDUCTING STATE OF λ-(BETS)2FeCl4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3101-3104
Author(s):  
L. BALICAS ◽  
J. S. BROOKS ◽  
K. STORR ◽  
S. UJI ◽  
M. TOKUMOTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Superconducting State ◽  
Ground State ◽  
Electrical Transport ◽  
High Field ◽  
Two Dimensional ◽  
Exchange Field ◽  
Organic Conductor ◽  
Field Phase ◽  
Antiferromagnetic Ground State

We investigate by electrical transport the field-induced superconducting state (FISC) in the organic conductor λ- (BETS) 2 FeCl 4. Below 4 K, antiferromagnetic-insulator, metallic, and eventually superconducting (FISC) ground states are observed with increasing in-plane magnetic field. The FISC state survives between 18 and 41 T, and can be interpreted in terms of the Jaccarino-Peter effect, where the external magnetic field compensates the exchange field of aligned Fe 3+ ions. We further argue that the Fe 3+ moments are essential to stabilize the resulting singlet, two-dimensional superconducting state. Here we provide experimental evidence indicating that this state, as well as the insulating antiferromagnetic ground state, is extremely sensitive to hydrostatic pressure.

scholarly journals Zur Lösung des quantenmechanischen Drei-Körper-Problems

1968 ◽  
Vol 23 (4) ◽  
pp. 579-596
Author(s):  
H. Ruder
Keyword(s):  
Ground State ◽  
Physical Meaning ◽  
State Energy ◽  
Differential Operators ◽  
Perturbation Expansion ◽  
Reflection Symmetry ◽  
Body System ◽  
Rapid Convergence ◽  
Symmetry Properties ◽  
Three Body

For the description of a three-body-system 6 coordinates are introduced which take full advantage of the symmetry properties of the system. The Schrödinger equation in these coordinates is derived. Using rotational and reflection symmetry one obtains a set of l respectively l+1 coupled differential equations containing only the 3 coordinates of the triangle formed by the 3 masses. Solutions are given for special potentials and arbitrary l. The physical meaning of the differential operators appearing in the equations becomes evident from their application to the solution functions. This leads to a rearrangement of the Hamiltonian in a very transparent form and gives a hint how to get the most effective perturbation expansion. A simple example is worked out. For systems with Coulomb interaction a modification of the method is suggested by physical considerations. The calculation of the ground state energy of the Helium atom shows the rapid convergence of the procedure.

Wave-number dependence of the static screening function of an interacting electron gas. II. Higher-order exchange and correlation effects

1970 ◽  
Vol 48 (2) ◽  
pp. 167-181 ◽  
Author(s):  
D. J. W. Geldart ◽  
Roger Taylor
Keyword(s):  
Density Dependence ◽  
Ground State ◽  
Electron Gas ◽  
Perturbation Expansion ◽  
Interpolation Formula ◽  
Higher Order ◽  
Wave Number ◽  
Correlation Effects ◽  
Many Body ◽  
Static Screening

An interpolation formula is suggested for the wave-number and density dependence of the static screening function for an interacting electron gas in its ground state. The approximate screening function simulates a number of properties of the exact screening function which have been established by analysis of its many-body perturbation expansion. The accuracy of the interpolation formula is discussed and is considered to be adequate for practical calculations in the range of intermediate metallic densities.

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