lammps/lib/atc/ElectronFlux.h

97 lines
3.5 KiB
C++

#ifndef ELECTRON_FLUX_H
#define ELECTRON_FLUX_H
#include <map>
#include <string>
using std::map;
using std::string;
#include "MatrixLibrary.h"
#include "ATC_TypeDefs.h"
namespace ATC {
class ElectronFlux
{
public:
ElectronFlux() {};
virtual ~ElectronFlux() {};
/** computes flux */
virtual void electron_flux(const FIELDS &fields,
const GRAD_FIELDS &gradFields,
GRAD_FIELD &flux)=0;
};
//-----------------------------------------------------------------------
class ElectronFluxLinear : public ElectronFlux
{
public:
ElectronFluxLinear(fstream &matfile, map<string,double> & parameters);
virtual ~ElectronFluxLinear() {};
virtual void electron_flux(const FIELDS &fields,
const GRAD_FIELDS &gradFields,
GRAD_FIELD &flux)
{
// J_n = - \mu n grad \phi - D grad n
const FIELD & n = (fields.find(ELECTRON_DENSITY))->second;
const GRAD_FIELD & dn =(gradFields.find(ELECTRON_DENSITY))->second;
const GRAD_FIELD & dphi =(gradFields.find(ELECTRIC_POTENTIAL))->second;
// NOTE use electron velocity instead
flux.push_back(-electronMobility_*dphi[0]);
flux.push_back(-electronMobility_*dphi[1]);
flux.push_back(-electronMobility_*dphi[2]);
flux[0] *= n; // scale by n to get : -n \mu grad(\phi)
flux[1] *= n;
flux[2] *= n;
flux[0] += -electronDiffusivity_* dn[0];
flux[1] += -electronDiffusivity_* dn[1];
flux[2] += -electronDiffusivity_* dn[2];
};
protected:
double electronMobility_, electronDiffusivity_;
};
//-----------------------------------------------------------------------
class ElectronFluxThermopower : public ElectronFlux
{
public:
ElectronFluxThermopower(fstream &matfile,map<string,double> & parameters);
virtual ~ElectronFluxThermopower() {};
virtual void electron_flux(const FIELDS &fields,
const GRAD_FIELDS &gradFields,
GRAD_FIELD &flux)
{
static const double kB_ = 8.617343e-5;// [eV/K]
// J_n = - \mu n grad \phi - \mu kB/e T_e grad n
// - \mu S n grad T_e - \mu kB/e n grad T_e
const FIELD & n = (fields.find(ELECTRON_DENSITY))->second;
const GRAD_FIELD & dn =(gradFields.find(ELECTRON_DENSITY))->second;
const GRAD_FIELD & dphi =(gradFields.find(ELECTRIC_POTENTIAL))->second;
const GRAD_FIELD & dT =(gradFields.find(ELECTRON_TEMPERATURE))->second;
flux.push_back(-electronMobility_*dphi[0]);
flux.push_back(-electronMobility_*dphi[1]);
flux.push_back(-electronMobility_*dphi[2]);
double coef = -electronMobility_*(seebeckCoef_ + kB_);
flux[0] += coef* dT[0];
flux[1] += coef* dT[1];
flux[2] += coef* dT[2];
flux[0] *= n; // scale by n
flux[1] *= n;
flux[2] *= n;
GRAD_FIELD tmp = dn;
const FIELD & Te = (fields.find(ELECTRON_TEMPERATURE))->second;
tmp[0] *= Te;
tmp[1] *= Te;
tmp[2] *= Te;
coef = -electronMobility_*kB_; // kB: eV/K/e -> V/K
flux[0] += tmp[0];
flux[1] += tmp[1];
flux[2] += tmp[2];
};
protected:
double electronMobility_, seebeckCoef_;
};
}
#endif