We have performed a theoretical study of the cyclotron effective mass and electron effective Land́ g∥ factor in semiconductor GaAs- Ga1-x Alx As quantum wells under an applied magnetic field parallel to the growth direction of the quantum well. The theoretical approach is within the nonparabolic and effective-mass approximation and via an Ogg-McCombe effective Hamiltonian [Proc. Phys. Soc. London 89, 431 (1969); Phys. Rev. 181, 1206 (1969)] for the electron in the conduction band of the GaAs- Ga1-x Alx As heterostructure, which allows a unified treatment of both the cyclotron mass and g∥ factor. Calculations are performed for different widths of the GaAs- Ga1-x Alx As quantum wells and as functions of the applied magnetic field, with results in very good agreement with reported experimental measurements of the electron cyclotron effective mass and g∥ factor. © 2006 American Institute of Physics.9910 Nielsen, M.A., Chuang, I.L., (2000) Quantum Computation and Quantum Information, , Cambridge University Press, CambridgeZutic, I., Fabian, J., Das Sarma, S., (2004) Rev. Mod. Phys., 76, p. 323Engel, H.-A., Loss, D., (2005) Science, 309, p. 586Singleton, J., Nicholas, R.J., Rogers, D.C., (1988) Surf. Sci., 196, p. 429Michels, J.G., Warbuton, R.J., Nicholas, R.J., Harris, J.J., Foxon, C.T., (1993) Physica B, 184, p. 159Le Jeune, P., Robart, D., Marie, X., Amand, T., Brosseau, M., Barrau, J., Kalevich, V., Rodichev, D., (1997) Semicond. Sci. Technol., 12, p. 380Malinowski, A., Harley, R.T., (2000) Phys. Rev. B, 62, p. 2051Hanson, R., Witkamp, B., Vandersypen, L.M.K., Van Beveren, L.H.W., Ellerman, J.M., Kouwenhoven, L.P., (2003) Phys. Rev. Lett., 91, p. 196802De Sousa, R., Das Sarma, S., (2003) Phys. Rev. B, 68, p. 155330Prado, S.J., Trallero-Giner, C., Alcalde, A.M., Lopez-Richard, V., Marques, G.E., (2004) Phys. Rev. B, 69, p. 201310Destefani, C.F., Ulloa, S.E., (2005) Phys. Rev. B, 71, p. 161303Kato, Y.K., Myers, R.C., Gossard, A.C., Awschalom, D.D., (2004) Science, 306, p. 1910Johnson, G.R., Kana-Ah, A., Cavenett, B.C., Skolnick, M.S., Baas, S.J., (1987) Semicond. Sci. Technol., 2, p. 182Dobers, M., Von Klitzing, K., Weimann, G., (1988) Phys. Rev. B, 38, p. 5453Snelling, M.J., Flin, G.P., Plaut, A.S., Harley, R.T., Tropper, A.C., Eccleston, R., Phillips, C.C., (1991) Phys. Rev. B, 44, p. 11345Heberle, A.P., Rühle, W.W., Ploog, K., (1994) Phys. Rev. Lett., 72, p. 3887Hannak, R.M., Oestreich, M., Heberle, A.P., Ruhle, W.W., Kohler, K., (1995) Solid State Commun., 93, p. 313Sapega, V.F., Ruf, T., Cardona, M., Ploog, K., Ivchenko, E.L., Mirlin, D.N., (1994) Phys. Rev. B, 50, p. 2510Medeiros-Ribeiro, G., Pinheiro, M.V.B., Pimentel, V.L., Marega, E., (2002) Appl. Phys. Lett., 80, p. 4229Lindermann, S., Ihn, T., Heinzel, T., Zwerger, W., Ensslin, K., Marancwski, K., Gossard, A.C., (2002) Phys. Rev. B, 66, p. 195314Kato, Y.K., Myers, R.C., Driscol, D.C., Gossard, A.C., Levy, J., Awschalom, D.D., (2003) Science, 299, p. 1201Bracker, A.S., (2005) Phys. Rev. Lett., 94, p. 047402Ogg, N.R., (1966) Proc. Phys. Soc. London, 89, p. 431McCombe, B.O., (1969) Phys. Rev., 181, p. 1206Morrow, R.A., Brownstein, K.R., (1984) Phys. Rev. B, 30, p. 678Braun, M., Rossler, U., (1985) J. Phys. C, 18, p. 3365Golubev, V.G., Ivanov-Omskii, V.I., Minervin, I.G., Osutin, A.V., Polyakov, D.G., (1985) Sov. Phys. JETP, 61, p. 1214Lommer, G., Malcher, F., Rössler, U., (1986) Superlattices Microstruct., 2, p. 273De Dios-Leyva, M., Lopez-Gondar, J., Del Valle, J.S., (1988) Phys. Status Solidi B, 148, p. 113. , 0370-1972Del Valle, J.S., Lopez-Gondar, J., De Dios-Leyva, M., (1989) Phys. Status Solidi B, 151, p. 127Ivchenko, E.L., Kiselev, A.A., (1992) Sov. Phys. Semicond., 26, p. 827Bruno-Alfonso, A., Diago-Cisneros, L., De Dios-Leyva, M., (1995) J. Appl. Phys., 77, p. 2837Li, E.H., (2000) Physica e (Amsterdam), 5, p. 215Dresselhaus, G., (1955) Phys. Rev., 100, p. 580Mendez, E.E., Esaki, L., Wang, W.I., (1986) Phys. Rev. B, 33, p. 2893