Exemple #1
0
def Junc_eff_Ham_gen(omega,
                     Wj,
                     Lx,
                     cutxT,
                     cutyT,
                     cutxB,
                     cutyB,
                     ax,
                     ay,
                     kx,
                     m_eff,
                     alp_l,
                     alp_t,
                     mu,
                     Vj,
                     Gam,
                     delta,
                     phi,
                     Vsc=0,
                     Gam_SC_factor=0,
                     iter=50,
                     eta=0,
                     plot_junction=False):
    # Generates the effective Hamiltonian for the Junction, which includes the self-energy from both of the SC regions
    # * omega is the (real) energy that goes into the Green's function
    # * W is the width of the junction
    # * ay_targ is the targeted lattice constant
    # * kx is the wavevector along the length of the junction
    # * m_eff is the effective mass
    # * alp_l is the longitudinal spin-orbit coupling coefficient
    # * alp_t is the transverse spin-orbit coupling coefficient
    # * mu is the chemical potential
    # * Vj is an addition potential in the junction region (V = 0 in SC regions by convention)
    # * Gam is the Zeeman energy in the junction
    # * Gam_SC = Gam_SC_factor * Gam, which is the Zeeman energy in the SC regions
    # * delta is the magnitude of the SC pairing in the SC regions
    # * phi is the phase difference between the two SC regions
    # * iter is the number of iteration of the algorithm to perform
    # * eta is the imaginary component of the energy that is used for broadening
    if cutxT == 0 and cutxB == 0:
        Nx = 3
        Lx = Nx * ax
    else:
        Nx = int(Lx / ax)

    Wj_int = int(
        Wj / ay
    )  # number of lattice sites in the junction region (in the y-direction)
    Ny = Wj_int + 2  #add one SC site on each side

    coor = shps.square(Nx, Ny)  #square lattice
    NN = nb.NN_sqr(coor)
    NNb = nb.Bound_Arr(coor)

    Gam_SC = Gam_SC_factor * Gam

    H_J = spop.HBDG(coor=coor,
                    ax=ax,
                    ay=ay,
                    NN=NN,
                    NNb=NNb,
                    Wj=Wj_int,
                    cutxT=cutxT,
                    cutyB=cutyB,
                    cutxB=cutxB,
                    cutyT=cutyT,
                    Vj=Vj,
                    Vsc=Vsc,
                    mu=mu,
                    gamx=Gam,
                    alpha=alp_l,
                    delta=delta,
                    phi=phi,
                    qx=kx,
                    meff_sc=m_eff,
                    meff_normal=m_eff,
                    plot_junction=plot_junction)

    Gs, Gb, sNRG_bot = bot_SC_sNRG_calc(omega=omega,
                                        Wj=Wj,
                                        Lx=Lx,
                                        cutxT=cutxT,
                                        cutxB=cutxB,
                                        ax=ax,
                                        ay=ay,
                                        kx=kx,
                                        m_eff=m_eff,
                                        alp_l=alp_l,
                                        alp_t=alp_t,
                                        mu=mu,
                                        Gam_SC=Gam_SC,
                                        delta=delta,
                                        phi=phi,
                                        iter=iter,
                                        eta=eta)

    Gs, Gb, sNRG_top = top_SC_sNRG_calc(omega=omega,
                                        Wj=Wj,
                                        Lx=Lx,
                                        cutxT=cutxT,
                                        cutxB=cutxB,
                                        ax=ax,
                                        ay=ay,
                                        kx=kx,
                                        m_eff=m_eff,
                                        alp_l=alp_l,
                                        alp_t=alp_t,
                                        mu=mu,
                                        Gam_SC=Gam_SC,
                                        delta=delta,
                                        phi=phi,
                                        iter=iter,
                                        eta=eta)

    #print(H_J.shape)
    #print(sNRG_top.shape)
    #print(sNRG_bot.shape)
    H_eff = H_J + sNRG_bot + sNRG_top
    return H_eff
Exemple #2
0
cuty = 0 #height of nodule
Nx, Ny, cutx, cuty, Wj = check.junction_geometry_check(Nx, Ny, cutx, cuty, Wj)
print("Nx = {}, Ny = {}, cutx = {}, cuty = {}, Wj = {}".format(Nx, Ny, cutx, cuty, Wj))

Junc_width = Wj*ay*.10 #nm
SC_width = ((Ny - Wj)*ay*.10)/2 #nm
Nod_widthx = cutx*ax*.1 #nm
Nod_widthy = cuty*ay*.1 #nm
print("Nodule Width in x-direction = ", Nod_widthx, "(nm)")
print("Nodule Width in y-direction = ", Nod_widthy, "(nm)")
print("Junction Width = ", Junc_width, "(nm)")
print("Supercondicting Lead Width = ", SC_width, "(nm)")
###################################################coor = shps.square(Nx, Ny) #square lattice
coor = shps.square(Nx, Ny) #square lattice
NN = nb.NN_sqr(coor)
NNb = nb.Bound_Arr(coor)
lat_size = coor.shape[0]

Lx = (max(coor[:, 0]) - min(coor[:, 0]) + 1)*ax #Unit cell size in x-direction
Ly = (max(coor[:, 1]) - min(coor[:, 1]) + 1)*ay #Unit cell size in y-direction
###################################################
#Defining Hamiltonian parameters
alpha = 100 #Spin-Orbit Coupling constant: [meV*A]
phi = np.pi #SC phase difference
delta = 1 #Superconducting Gap: [meV]
Vsc = 0 #Amplitude of potential in SC region: [meV]
Vj = 0 #Amplitude of potential in junction region: [meV]
V = Vjj(coor, Wj = Wj, Vsc = Vsc, Vj = Vj, cutx = cutx, cuty = cuty)

mu_i = 0
mu_f = 20.0
Exemple #3
0
    nod_bool = False

Junc_width = Wj*ay*.10 #nm
SC_width = ((Ny - Wj)*ay*.10)/2 #nm
Nod_widthx = cutx*ax*.1 #nm
Nod_widthy = cuty*ay*.1 #nm
print("Nodule Width in x-direction = ", Nod_widthx, "(nm)")
print("Nodule Width in y-direction = ", Nod_widthy, "(nm)")
print("Junction Width = ", Junc_width, "(nm)")
print("Supercondicting Lead Width = ", SC_width, "(nm)")

###################################################

coor = shps.square(Nx, Ny) #square lattice
NN = nb.NN_Arr(coor) #neighbor array
NNb = nb.Bound_Arr(coor) #boundary array
lat_size = coor.shape[0]
print("Lattice Size: ", lat_size)

Lx = (max(coor[:, 0]) - min(coor[:, 0]) + 1)*ax #Unit cell size in x-direction
Ly = (max(coor[:, 1]) - min(coor[:, 1]) + 1)*ay #Unit cell size in y-direction

###################################################
#Hamiltonian Parameters
alpha = 100 #Spin-Orbit Coupling constant: [meV*A]
gx = 0.2 #parallel to junction: [meV]
gz = 0 #normal to plane of junction: [meV]
phi = 0*np.pi #SC phase difference
delta = 1.0 #Superconducting Gap: [meV]
V0 = 50 #Amplitude of potential: [meV]
V = V_BL(coor, Wj = Wj, cutx=cutx, cuty=cuty, V0 = V0)