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Implementation of multilayer 2TM #119

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Implementation of multilayer 2TM #119

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13 changes: 12 additions & 1 deletion hdr/sim.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,7 @@
#include <vector>

/// Enumerated lists for code readability
enum pump_functions_t {square=0, two_temperature, double_pump_two_temperature, double_pump_square};
enum pump_functions_t {square=0, two_temperature, double_pump_two_temperature, double_pump_square, multilayer_two_temperature};

namespace sim{

Expand Down Expand Up @@ -150,6 +150,17 @@ namespace sim{
extern double TTG; ///electron coupling constant
extern double TTTe; /// electron temperature
extern double TTTp; /// phonon temperature

//Modified by M Strungaru
extern double TTcutofftime; //cutoff time for the laser pulse (in s)
extern double TTdamp; //damping after the TTcutofftime
extern double TTephrat; //ratio between the new electron-phonon coupling and old one
extern double TT_afterpp;
//for substrate
extern double TTCe_sub; ///electron specific heat
extern double TTCl_sub; ///phonon specific heat
extern double TTG_sub; ///electron coupling constant


extern int system_simulation_flags;
extern int hamiltonian_simulation_flags[10];
Expand Down
75 changes: 75 additions & 0 deletions src/program/temperature_pulse.cpp
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Expand Up @@ -54,6 +54,7 @@ double two_temperature_function(double ftime);
double double_pump_two_temperature_function(double ftime);
double square_temperature_function(double ftime);
double double_pump_square_temperature_function(double ftime);
double multilayer_two_temperature_function(double ftime);

/// Selects appropriate temperature pulse function according to user input
double temperature_pulse_function(double function_time){
Expand All @@ -75,6 +76,10 @@ double temperature_pulse_function(double function_time){
case(double_pump_square):
return double_pump_square_temperature_function(function_time);
break;

case (multilayer_two_temperature):
return multilayer_two_temperature_function(function_time);
break;

default:
return 0.0;
Expand Down Expand Up @@ -226,6 +231,76 @@ double double_pump_square_temperature_function(double ftime){

}

//modified by M Strungaru
double multilayer_two_temperature_function(double ftime){

const double i_pump_time = 1.0/sim::pump_time;
const double reduced_time = (ftime-3.*sim::pump_time)*i_pump_time;
const double four_ln_2 = 2.77258872224; // 4 ln 2
// 2/(delta sqrt(pi/ln 2))*0.1, delta = 10 nm, J/m^2 -> mJ/cm^2 (factor 0.1)
const double two_delta_sqrt_pi_ln_2 = 9394372.787;
const double pump=sim::pump_power*two_delta_sqrt_pi_ln_2*
exp(-four_ln_2*reduced_time*reduced_time)*i_pump_time;

const double Te = sim::TTTe;
const double Tp = sim::TTTp;
const double G = sim::TTG;
const double Ce = sim::TTCe;
const double Cl = sim::TTCl;
const double dt = mp::dt_SI;

//two temperature model parameters for substrate
double G1 = sim::TTG_sub;
const double Ce1 = sim::TTCe_sub;
const double Cl1 = sim::TTCl_sub;


if(ftime>=sim::TTcutofftime){
//pump=sim::TT_afterpp;
//G=sim::TTG*sim::TTephrat;

//std::cout<<"ftime22 "<<sim::TTcutofftime<<"\t"<<pump<<"\t"<<sim::TTephrat<<"\t"<< sim::TTdamp<<std::endl;
//std::cout<<"2 Hth "<<mp::material[0].H_th_sigma<<std::endl;
for(unsigned int mat=0;mat<mp::material.size();mat++){
mp::material[mat].alpha=sim::TTdamp;
mp::material[mat].one_oneplusalpha_sq = -mp::material[mat].gamma_rel/(1.0+mp::material[mat].alpha*mp::material[mat].alpha);
mp::material[mat].alpha_oneplusalpha_sq = mp::material[mat].alpha*mp::material[mat].one_oneplusalpha_sq;
mp::material[mat].H_th_sigma= sqrt(2.0*mp::material[mat].alpha*1.3806503e-23 / (mp::material[mat].mu_s_SI*mp::material[mat].gamma_rel*mp::dt));
}
}
// integrate two temperature model (floor in free elecron approximation (c prop to T) for low temperatures)
//normal integration of 22TM without heat sink coupling
if(ftime<sim::TTcutofftime){

if(Te>1.0) sim::TTTe = (-G*(Te-Tp)+pump)*dt/(Ce*Te) + Te;
else sim::TTTe = (-G*(Te-Tp)+pump)*dt/Ce + Te;
sim::TTTp = ( G*(Te-Tp) )*dt/Cl + Tp; //- (Tp-sim::Teq)*sim::HeatSinkCouplingConstant*dt;
}
else {
//integrate the other parameters for 2ttm
if(Te>1.0) sim::TTTe = (-G1*(Te-Tp)+pump)*dt/(Ce1*Te) + Te;
else sim::TTTe = (-G1*(Te-Tp)+pump)*dt/Ce1 + Te;
sim::TTTp = ( G1*(Te-Tp) )*dt/Cl1 + Tp - (Tp-sim::Teq)*sim::HeatSinkCouplingConstant*dt;
}


// Optionally set material specific temperatures
if(sim::local_temperature==true){
for(unsigned int mat=0;mat<mp::material.size();mat++){
if(mp::material[mat].couple_to_phonon_temperature==true) mp::material[mat].temperature=sim::TTTp;
else mp::material[mat].temperature=sim::TTTe;
}
}

if(ftime<sim::TTcutofftime)
return sim::TTTe;
else
return sim::TTTp;


}


namespace program{
/// @brief Function to calculate a time series with two temperature model heating/cooling profile
///
Expand Down
10 changes: 10 additions & 0 deletions src/simulate/sim.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,16 @@ namespace sim{
double TTTe = 0.0; /// electron temperature
double TTTp = 0.0; /// phonon temperature

//created by M Strungaru
double TTcutofftime=500E-15; //cutoff time for the laser pulse (in s)
double TTdamp=0.001; //damping after the TTcutofftime
double TTephrat=100; //ratio between the new electron-phonon coupling and old one
double TT_afterpp=0.0;
double TTCe_sub = 222.0; ///electron specific heat (gamma)
double TTCl_sub = 2.3E06; ///phonon specific heat
double TTG_sub = 6.6E17 ;///electron coupling constant


int system_simulation_flags;
int hamiltonian_simulation_flags[10];

Expand Down
64 changes: 64 additions & 0 deletions src/vio/match.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -417,6 +417,11 @@ namespace vin{
if(value==test){
sim::pump_function=double_pump_square;
return EXIT_SUCCESS;
}
test="multilayer-two-temperature";
if(value==test){
sim::pump_function=multilayer_two_temperature;
return EXIT_SUCCESS;
}
else{
terminaltextcolor(RED);
Expand Down Expand Up @@ -510,6 +515,65 @@ namespace vin{
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
//--------------------------------------------------------------------
//Modified by M Strungaru 2024
test="two-temperature-damping";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TTdamp=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
test="two-temperature-cutoff-time";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TTcutofftime=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
test="two-temperature-e-ph-ratio";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TTephrat=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
test="two-temperature-after-pulse-power";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TT_afterpp=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
test="two-temperature-substrate-electron-heat-capacity";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TTCe_sub=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
test="two-temperature-substrate-phonon-heat-capacity";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TTCl_sub=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------
test="two-temperature-substrate-electron-phonon-coupling";
if(word==test){
double hscc=atof(value.c_str());
check_for_valid_value(hscc, word, line, prefix, unit, "none", 0.0, 1.0e40,"input","0.0 - 1.0E40");
sim::TTG_sub=hscc;
return EXIT_SUCCESS;
}
//--------------------------------------------------------------------

test="cooling-function";
if(word==test){
test="exponential";
Expand Down