Dr. George Martins
Assistant Professor
Physics Department - Oakland University
2200 N. Squirrel Rd.
48309 - Rochester - MI
Ph. (248) 370-3417 / FAX (248) 370-3408
martins@oakland.edu

Research Activities

My basic research interests are in the area of strongly correlated electrons. In colaboration with research groups in the United States, Europe and Brazil, I have been applying different numerical techniques to probe and understand the properties of strongly correlated electronic systems. 'Strongly correlated condensed matter' is truly a vast area and there are a variety of different computational techniques that can be applied to obtain understanding of their multi-faceted behavior. I have concentrated for now on Exact Diagonalization Methods as a tool to gain understanding of nano structures, High- Tc cuprates, ladders and spin chains and more recently frustrated spin systems.

Publications

  1. 'Transport properties of strongly correlated electrons in quantum dots studied with a simple circuit model'
    Martins GB, Busser CA, Al-Hassanieh KA, Anda EV, Moreo A, Dagotto E
    Physical Review Letters 96 (6) 066802 (2006)

  2. 'Electron transport through a molecular conductor with center-of-mass motion'
    Al-Hassanieh KA, Busser CA, Martins GB, Dagotto E
    Physical Review Letters 95 (25) 256807 (2005) pdf file

  3. 'New results for the t-J model in ladders: changes in the spin liquid state with applied magnetic field; implications for the cuprates'
    Albuquerque AF, Martins GB
    Journal of Physics: Cond. Matt. 17 (15) 2419 (2005) pdf file

  4. 'Prediction of ferromagnetic correlations in coupled double-level quantum dots'
    Martins GB, Busser CA, Al-Hassanieh KA, Moreo A, Dagotto E
    Physical Review Letters 94 (2) 026804 (2004) pdf file

  5. 'Interference effects in the conductance of multilevel quantum dots'
    Busser CA, Martins GB, Al-Hassanieh KA, Moreo A, Dagotto E
    Physical Review B 70 (24) 245303 (2004) pdf file

  6. 'Superconductivity in the two-dimensional t-J model'
    Sorella S, Martins GB, Becca F, Gazza C, Capriotti L, Parola A, Dagotto E
    Physical Review Letters 88 (11) 7002 (2002) pdf file

  7. 'Hole-pair symmetry and excitations in the strong-coupling extended t-Jz model: competition between p-wave and d-wave'
    Fye RM, Martins GB, Dagotto E
    Physical Review B 69 (22) 224507 (2004) pdf file

  8. 'Qualitative understanding of the sign of t' asymmetry in the extended t-J model and relevance for pairing properties'
    Martins GB, Xavier JC, Arrachea L, Dagotto E
    Physical Review B 64 (18) 513 (2001) pdf file

  9. 'Hole pairs in a spin liquid: Influence of electrostatic hole-hole repulsion'
    Gazza C, Martins GB, Riera J, Dagotto E
    Physical Review B 59 (2) R709 (1999) pdf file

  10. 'Indications of spin-charge separation at short distance and stripe formation in the extended t-J model on ladders and planes'
    Martins GB, Xavier JC, Gazza C, Vojta M, Dagotto E
    Physical Review B 63 (1) 4414 (2001) pdf file

  11. 'Indications of spin-charge separation in the two-dimensional extended t-J model'
    Martins GB, Eder R, Dagotto E
    Physical Review B 60 (6) R3716 (1999) pdf file

  12. 'Stripes in the Ising limit of models for the cuprates'
    Martins GB, Gazza C, Dagotto E
    Physical Review B 62 (21) 13929 (2000) pdf file

  13. 'Doped stripes in models for the cuprates emerging from the one-hole properties of the insulator'
    Martins GB, Gazza C, Xavier JC, Feiguin A, Dagotto E
    Physical Review Letters 84 (25) 5844 (2000) pdf file

  14. 'Doped stripes evolving from the one-hole properties of the antiferromagnetic insulator'
    Dagotto E, Martins GB
    International Journal of Modern Physics B 14 (29-31) 3424 (2000)

  15. 'Diagonalization in reduced Hilbert spaces using a systematically improved basis: Application to spin dynamics in lightly doped ladders'
    Dagotto E, Martins GB, Riera J, Malvezzi AL, Gazza C
    Physical Review B 58 (18) 12063 (1998) pdf file

  16. 'Hole-density evolution of the one-particle spectral function in doped ladders'
    Martins GB, Gazza C, Dagotto E
    Physical Review B 59 (21) 13596 (1999) pdf file

  17. 'Qualitative understanding of the sign of t' asymmetry in the extended t-J model and relevance for pairing properties'
    Martins GB, Xavier JC, Arrachea L, Dagotto E
    Physical Review B 64 (18) 513 (2001) pdf file

  18. 'Hole pairs in a spin liquid: Influence of electrostatic hole-hole repulsion'
    Gazza C, Martins GB, Riera J, Dagotto E
    Physical Review B 59 (2) R709 (1999) pdf file

  19. 'Enhancement of antiferromagnetic correlations induced by nonmagnetic impurities: Origin and predictions for NMR experiments'
    Laukamp M, Martins GB, Gazza C, Malvezzi AL, Dagotto E, Hansen PM, Lopez AC, Riera J
    Physical Review B 57 (17) 10755 (1998) pdf file

  20. 'Local enhancement of antiferromagnetic correlations by nonmagnetic impurities'
    Martins GB, Laukamp M, Riera J, Dagotto E
    Physical Review Letters 78 (18) 3563 (1997) pdf file

  21. 'Rapid suppression of the spin gap in Zn-doped CuGeO3 and SrCu2O3'
    Martins GB, Dagotto E, Riera JA
    Physical Review B 54 (22) 16032 (1996) pdf file

  22. 'High-field electron spin resonance of Cu1-x Znx Ge O3'
    Hassan AK, Pardi LA, Martins GB, Cao G, Brunel LC
    Physical Review Letters 80 (09) 1984 (1998) pdf file

  23. 'Anomalous NMR magnetic shifts in CeCoIn5'
    Curro NJ, Simovic B, Hammel PC, Pagliuso P, Sarrao J, Thompson JD, Martins GB
    Physical Review B 64 (18) R514 (2001) pdf file

  24. 'Magnetic properties of the frustrated antiferromagnetic spinel ZnCr2O4 and the spin-glass Zn1-xCdxCr2O4 (x=0.05,0.10)'
    Martinho H, Moreno NO, Sanjurjo JA, Rettori C, Garcia-Adeva AJ, Huber DL, Oseroff SB, Ratcliff W, Cheong SW, Pagliuso PG, Sarrao JL, Martins GB
    Physical Review B 64 (02) 4408 (2001) pdf file

  25. 'Structural effects in the EPR spectra of Ni3+ in La2Ni0.5Li 0.5O4'
    Urbano RR, Garcia A, Granado E, Sanjurjo JA, Torriani I, Rettori C, Oseroff SB, Hassan A, Martins GB, Fisk Z, Pagliuso PG, Sarrao JL, Caciuffo R
    Physical Review B 62 (14) 9593 (2000) pdf file

  26. 'Spin-Lattice interaction for ions in low-symmetry sites – the case of Mn2+:CaCO3'
    Barberis GE, Martins GB, Calvo R
    Physical Review B 49 (13) 8583 (1994) pdf file

  27. 'Crystal-field study in rare-earth-doped semiconducting YBiPt'
    Pagliuso PG, Rettori C, Torelli ME, Martins GB, Fisk Z, Sarrao JL, Hundley MF, Oseroff SB
    Physical Review B 60 (6) 4176 (1999) pdf file

  28. 'Crystal field study in rare-earth-doped LuInNi4'
    Pagliuso PG, Thompson JD, Sarrao JL, Sercheli MS, Rettori C, Martins GB, Fisk Z, Oseroff SB
    Physical Review B 63 (14) 4430 (2001) pdf file

  29. 'Different Pr3+ environments in Pr1.85Ce0.15CuO4 – A Raman crystal-field study'
    Sanjurjo JA, Martins GB, Pagliuso PG, Granado E, Torrinai I, Rettori C, Oseroff S, Fisk Z
    Physical Review B 51 (02) 1185 (2001) pdf file

  30. 'ESR of Gd3+ and Er3+ in Pr2-xCexCuO4'
    Martins GB, Rao D, Valdivia JA, Pires MA, Barberis GE, Rettori C, Venegas PA, Oseroff S, Fisk Z Physical Review B 51 (17) 11909 (1995) pdf file

  31. 'Electron Spin Resonance of Nd3+ and Yb3+ in CeFe4P12'
    Martins GB, Pires MA, Barberis GE, Rettori C, Torikachvili MS
    Physical Review B 50 (20) 14822 (1994) pdf file

  32. 'Ferromagnetism and crystal fields in YbInNi4'
    Sarrao JL, Modler R, Movshovich R, Lacerda AH, Hristova D, Cornelius AL, Hundley MF, Thompson JD, Benton CL, Immer CD, Torelli ME, Martins GB, Fisk Z, Oseroff SB
    Physical Review B 57 (13) 7785 (1998) pdf file