eshelbyTensorSpinPolarized.h

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//
// Copyright (c) 2017-2025 The Regents of the University of Michigan and DFT-FE
// authors.
//
// This file is part of the DFT-FE code.
//
// The DFT-FE code is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
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// the top level of the DFT-FE distribution.
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//
#ifndef eshelbySP_H_
#define eshelbySP_H_
#include "constants.h"
#include "headers.h"
 
namespace dftfe
{
  /**
   * @brief The functions in this namespace contain the expressions for the various terms of the configurational force (https://link.aps.org/doi/10.1103/PhysRevB.97.165132)
   * for both periodic and non-periodic case.
   *
   * The functions in this namespace are similar to the ones in eshelbyTensor.h
   * except the ones here are specialized
   * for spin polarized case. Spin0 and Spin1 refer to up and down spins
   * respectively. General nomenclature of the input arguments: a) phiTot- total
   * electrostatic potential b) phiExt- sum of electrostatic potential from all
   * nuclear charges c) rho- electron density d) gradRho- gradient of electron
   * density e) exc- exchange correlation energy f) derExcGradRho- derivative of
   * exc with gradient of rho g) psiBegin- begin iterator to vector eigenvectors
   * stored as a flattened array over k points and number of eigenvectors for
   * each k point (periodic case has complex valued eigenvectors which is why
   * dealii::Tensor<1,2,dealii::VectorizedArray<double> is used in functions for
   * periodic case) h) gradPsiBegin- gradient of eigenvectors i) eigenValues-
   * Kohn sham grounstate eigenvalues stored in a vector. For periodic problems
   * with multiple k points the outer vector should be over k points j) tVal-
   * smearing temperature in K k) pseudoVLoc- local part of the pseuodopotential
   * l) gradPseudoVLoc- gradient of local part of pseudopotential m) ZetaDeltaV-
   * nonlocal pseudowavefunctions times deltaV (see Eq. 11 in
   * https://link.aps.org/doi/10.1103/PhysRevB.97.165132) n) gradZetaDeltaV-
   * gradient of ZetaDeltaV o) projectorKetTimesPsiTimesV- nonlocal
   * pseudopotential projector ket times eigenvectors which are precomputed. The
   * nonlocal pseudopotential constants are also multiplied to this quantity.
   * (see Eq. 11 in https://link.aps.org/doi/10.1103/PhysRevB.97.165132)
   *
   * @author Sambit Das
   */
  namespace eshelbyTensorSP
  {
    /// exchange-correlation and psp part of the ELoc Eshelby tensor
    dealii::Tensor<2, 3, dealii::VectorizedArray<double>>
    getELocXcEshelbyTensor(
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>> &gradRhoSpin0,
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>> &gradRhoSpin1,
      const dealii::VectorizedArray<double> &                      exc,
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>>
        &derExcGradRhoSpin0,
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>>
        &derExcGradRhoSpin1);
 
 
 
    /// Nonlocal core correction pseudopotential force contribution
    dealii::Tensor<1, 3, dealii::VectorizedArray<double>>
    getFNonlinearCoreCorrection(
      const dealii::VectorizedArray<double> &vxcSpin0,
      const dealii::VectorizedArray<double> &vxcSpin1,
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>>
        &derExcGradRhoSpin0,
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>>
        &derExcGradRhoSpin1,
      const dealii::Tensor<1, 3, dealii::VectorizedArray<double>> &gradRhoCore,
      const dealii::Tensor<2, 3, dealii::VectorizedArray<double>>
        &        hessianRhoCore,
      const bool isXCGGA);
  }; // namespace eshelbyTensorSP
 
} // namespace dftfe
#endif