Update

simulate_bilayer_ferromagnet.m → simulate_bilayer_spinorbit.m

@@ -4,7 +4,7 @@
 % Created 2015-02-06
 % Updated 2015-05-07
 
-function simulate_bilayer_ferromagnet(exchange_strength, exchange_angle, spinorbit_strength, spinorbit_angle)
+function simulate_bilayer_spinorbit(exchange_strength, exchange_angle, spinorbit_strength, spinorbit_angle)
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     %                 DEFINE PARAMETERS FOR THE SIMULATION
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -14,7 +14,7 @@ function simulate_bilayer_ferromagnet(exchange_strength, exchange_angle, spinorb
     energies      = linspace(0.0, 1.5,  26);
 
     % Filename where results will be stored
-    output = 'simulate_bilayer_ferromagnet.dat';
+    output = 'simulate_bilayer_spinorbit.dat';
 
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     %                   PREPARATIONS FOR THE SIMULATION

simulate_bilayer_spinorbit_sc.m

@@ -0,0 +1,92 @@
+% This script simulates the proximity effect in a ferromagnet with SOC.
+% [This version of the script performs the calculation self-consistently.]
+%
+% Written by Jabir Ali Ouassou <[email protected]>
+% Created 2015-05-14
+% Updated 2015-05-14
+
+function simulate_bilayer_spinorbit_sc(exchange_strength, exchange_angle, spinorbit_strength, spinorbit_angle)
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    %                 DEFINE PARAMETERS FOR THE SIMULATION
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+    % Vectors of positions and energies that will be used in the simulation
+    positions = linspace(0, 1, 151);
+    energies  = [linspace(0.001,1.500,501) linspace(1.501,cosh(1/0.2),101)];
+
+    % Filename where results will be stored
+    output = 'simulate_bilayer_spinorbit_sc.dat';
+
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    %                   PREPARATIONS FOR THE SIMULATION
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+    % Make sure that all required classes and methods are in the current path
+    initialize;
+
+    % Create a superconductor [d=0.55ξ]
+    s = Superconductor(positions, energies, 1/0.55^2, 0.2);
+    s.interface_right = 3;
+    %s.locked = true;
+
+    % Create a ferromagnet [d=0.55ξ]
+    m = Ferromagnet(positions, energies, 1/0.55^2, [exchange_strength*cos(exchange_angle), exchange_strength*sin(exchange_angle), 0], SpinVector.RashbaDresselhaus(spinorbit_strength, spinorbit_angle));
+    m.interface_left = 3;
+    m.update_boundary_left(s);
+
+    % This enables or disables various debugging options
+    s.delay = 0;
+    s.debug = 1;
+    s.plot  = 0;
+
+    m.delay = 0;
+    m.debug = 1;
+    m.plot  = 0;
+
+    % These variables keep track of the density of states 
+    dosM = zeros(1,length(energies));
+    dosS = zeros(1,length(energies));
+
+    dosM0 = ones(1,length(energies));
+    dosS0 = ones(1,length(energies));
+
+    residue = 1;
+
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+    %                       PERFORM THE SIMULATION
+    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+    tic;
+    while residue > 1e-3
+        % Status information
+        fprintf('[ Time: %2d min ] [ Gap: %.4f ] [ Residue: %.4f ]\n',  floor(toc/60), s.gap_max, residue);
+
+        % Update the internal state of the normal metal
+        m.update_boundary_left(s);
+        m.update;
+
+        % Calculate the density of states in the normal metal [left end]
+        dosM0 = dosM;
+        for n=1:length(energies)
+            dosM(n) = m.states(1,n).eval_ldos;
+        end
+        fprintf('[ ZEP in ferromagnet: %.6f ]\n\n', dosM(1));
+
+        % Update the internal state of the superconductor
+        s.update_boundary_right(m);
+        s.update;
+
+        % Calculate the density of states in the superconductor [right end]
+        dosS0 = dosS;
+        for n=1:length(energies)
+            dosS(n) = s.states(end,n).eval_ldos;
+        end
+        fprintf('[ ZEP in superconductor: %.6f ]\n\n', dosS(1));
+
+        % Update the residue
+        residue = max(max(abs(dosM-dosM0)),max(abs(dosS-dosS0)));
+
+        % Save the results of the simulation
+        save(output);
+    end
+end

simulate_josephson_ferromagnet.m → simulate_josephson_spinorbit.m

@@ -5,7 +5,7 @@
 % Created 2015-05-06
 % Updated 2015-05-07
 
-function simulate_josephson_ferromagnet(phase_difference, exchange_strength, exchange_angle, spinorbit_strength, spinorbit_angle)
+function simulate_josephson_spinorbit(phase_difference, exchange_strength, exchange_angle, spinorbit_strength, spinorbit_angle)
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     %                 DEFINE PARAMETERS FOR THE SIMULATION
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@@ -15,7 +15,7 @@ function simulate_josephson_ferromagnet(phase_difference, exchange_strength, exc
     energies      = linspace(0.0, 1.5,  25);
 
     % Filename where results will be stored
-    output = 'simulate_josephson_ferromagnet.dat';
+    output = 'simulate_josephson_spinorbit.dat';
 
     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     %                   PREPARATIONS FOR THE SIMULATION
@@ -58,4 +58,4 @@ function simulate_josephson_ferromagnet(phase_difference, exchange_strength, exc
 
     % Save the results of the simulation
     save(output);
-end
+end