scholarly journals Ab initio methodology for magnetic exchange parameters: Generic four-state energy mapping onto a Heisenberg spin Hamiltonian

2020 ◽  
Vol 102 (1) ◽  
Author(s):  
D. Šabani ◽  
C. Bacaksiz ◽  
M. V. Milošević
Keyword(s):  
Ab Initio ◽  
State Energy ◽  
Spin Hamiltonian ◽  
Magnetic Exchange ◽  
Heisenberg Spin ◽  
Heisenberg Spin Hamiltonian ◽  
Energy Mapping ◽  
Exchange Parameters

Ab Initio Investigations of Structural and Magnetic Properties of Cr-Doped Ni-Co-Mn-Sn Heusler Alloys

2016 ◽  
Vol 845 ◽  
pp. 134-137
Author(s):  
Elizaveta E. Smolyakova ◽  
M.A. Zagrebin ◽  
V.V. Sokolovskiy ◽  
Vasiliy D. Buchelnikov
Keyword(s):  
Ab Initio ◽  
Nearest Neighbor ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Lattice Parameter ◽  
Neighbor Interaction ◽  
Magnetic Exchange ◽  
Cr Content ◽  
Crystal Lattice Parameters ◽  
Exchange Parameters

Ab initio calculations were performed to investigate composition dependences of crystal lattice parameters, magnetic moments,bulk modulus, magnetic exchange parameters inNi2-yCoyMn1.5-xCrxSn0.5 (y =0.2, 0.4; 0.0 ≤ x ≤ 0.4) Heusler alloys. It was shown that increasing of Cr content (x) firstly leads an increasing of lattice parameter, but then a decreasing. The strongest ferromagnetic (FM) interaction for Ni1.6Co0.4Mn1.4Cr0.1Sn0.5 is nearest-neighbor interaction between Co and Mn1 (on own sites). The strongest antiferromagnetic (AFM) interaction is observed between nearest-neighbor Mn1-Cr atoms in the first coordination sphere and it is equal to-15 meV. Total magnetic moment of Ni2-yCoyMn1.5-xCrxSn0.5 (y =0.2, 0.4; 0.0 ≤ x ≤ 0.4) takes value in region from 6.1 μB to 6.6 μB.

scholarly journals Dynamic creation of a topologically-ordered Hamiltonian using spin-pulse control in the Heisenberg model

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Tetsufumi Tanamoto ◽  
Keiji Ono ◽  
Yu-xi Liu ◽  
Franco Nori
Keyword(s):  
Quantum Information Processing ◽  
Pulse Sequence ◽  
Honeycomb Lattice ◽  
Pulse Control ◽  
Spin Hamiltonian ◽  
Heisenberg Spin ◽  
Important Approach ◽  
One Step ◽  
Heisenberg Spin Hamiltonian ◽  
Stable Material

Abstract Hamiltonian engineering is an important approach for quantum information processing, when appropriate materials do not exist in nature or are unstable. So far there is no stable material for the Kitaev spin Hamiltonian with anisotropic interactions on a honeycomb lattice, which plays a crucial role in the realization of both Abelian and non-Abelian anyons. Here, we show two methods to dynamically realize the Kitaev spin Hamiltonian from the conventional Heisenberg spin Hamiltonian using pulse-control techniques based on the Baker-Campbell-Hausdorff (BCH) formula. In the first method, the Heisenberg interaction is changed into Ising interactions in the first process of the pulse sequence. In the next process of the first method, we transform them to a desirable anisotropic Kitaev spin Hamiltonian. In the second more efficient method, we show that if we carefully design two-dimensional pulses that vary depending on the qubit location, we can obtain the desired Hamiltonian in only one step of applying the BCH formula. As an example, we apply our methods to spin qubits based on quantum dots, in which the effects of both the spin-orbit interaction and the hyperfine interaction are estimated.

scholarly journals Structural and magnetic properties of heusler alloys Pd2MnZ (Z=Ga, Ge, As): AB INITIO study

2018 ◽  
Vol 185 ◽  
pp. 05007 ◽  
Author(s):  
Olga Miroshkina ◽  
Mikhail Zagrebin ◽  
Vladimir Sokolovskiy ◽  
Vasiliy Buchelnikov
Keyword(s):  
Monte Carlo ◽  
Magnetic Properties ◽  
Ab Initio ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Magnetic Exchange ◽  
Valence Electrons ◽  
Martensitic State ◽  
Structural And Magnetic Properties ◽  
Exchange Parameters

In this work, we report results of ab initio and Monte Carlo investigations of structural and magnetic properties in a series of Heusler compositions Pd2MnZ (Z = Ga, Ge, As). It was found that for Pd2MnGa and Pd2MnAs, the stable martensitic state is realized on the contrast with Pd2MnGe. The equilibrium lattice parameters for the series of Pd2MnZ (Z = Ga, Ge, As) compounds increase with increasing the number of valence electrons per atom (e/a ratio). Having calculated total magnetic moments and magnetic exchange parameters from ab initio methods, the Curie temperature for Pd2Mn-based alloys has been estimated in the framework of Monte Carlo simulations of Heisenberg model.

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