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Positron annihilation lifetime spectroscopy (PALS) measurements of SmFeAsO polycrystalline sample were first carried out at 298 K. Two lifetime components of 1516 ps and 2903 ps were obtained. According to two-state capture model, the free annihilation lifetime in polycrystalline SmFeAsO is 1870 ps, which agrees well with the calculated value（in general gradient approximation） of 173 ps in SmFeAsO single crystal. Superposed-neutral-atom model and the finite-difference method (SNA-FD) were used to calculate the positron annihilation information in single-crystal SmFeAsO. The results show that the ratio of annihilation rate with valence electrons to annihilation rate with core electrons is 106, while the ratio of annihilation rate with electrons from Fe, As, Sm, and O atoms are 1∶13∶12∶1
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Keywords:
- high-temperature superconductors /
- positron lifetime
[1] ［1］McMillan W L 1968 Phys. Rev. 167 331
[2] ［2］Chen X H, Wu T, Wu G, Liu R H, Chen H, Fang D F 2008 Nature 453 761
[3] ［3］Plazaolat F, de Diegot N 1994 J. Phys. D: Condens. Matter 6 447
[4] ［4］Falub C V, Mijnarends P E, Eijt S W H, van Huis M A, van Veen A, Schut H 2002 Phys. Rev. B 66 075426
[5] ［5］Chen X L, Kong W, Weng H M, Ye B J 2008 Acta Phys. Sin. 57 3271 (in Chinese) ［陈祥磊、孔伟、翁惠民、叶邦角 2008 57 3271］
[6] ［6］Chen X L, Xi C Y, Ye B J, Weng H M 2007 Acta Phys. Sin. 56 6695 (in Chinese) ［陈祥磊、郗传英、叶邦角、翁惠民 2007 56 6695］
[7] ［7］Jensen K O 1989 J. Phys. D: Condens. Matter 1 10595
[8] ［8］Puska M J, Nieminen R M 1983 J. Phys. F: Met. Phys. 13
[9] ［9］Plazaola F, Seitsonent A P, Puska M J 1994 J. Phys. D: Condens. Matter 6 8809
[10] ］Boronski E, Nieminen R M 1986 Phys. Rev. B 34 3820
[11] ］Barbiellini B, Puska M J, Korhonen T, Harju A, Torsti T, Nieminen R M 1996 Phys. Rev. B 53 16201
[12] ］Liu R H, Wu G, Wu T, Fang D F, Chen H, Li S Y, Xie Y L, Wang X F, Yang R L, Ding L, He C, Feng D L, Chen X H 2008 Phys. Rev. Lett. 101 087001
[13] ］Liu L H, Dong C, Deng D M, Chen Z P, Zhang J C 2001 Acta Phys. Sin. 50 769 (in Chinese) ［刘丽华、董成、邓冬梅、陈镇平、张金仓 2001 50 769］
[14] ］Chen Z P, Zhang J C, Cao G X, Cao S X 2002 Acta Phys. Sin. 51 2150 (in Chinese) ［陈镇平、张金仓、曹桂新、曹世勋 2002 51 2150］
[15] -
[1] ［1］McMillan W L 1968 Phys. Rev. 167 331
[2] ［2］Chen X H, Wu T, Wu G, Liu R H, Chen H, Fang D F 2008 Nature 453 761
[3] ［3］Plazaolat F, de Diegot N 1994 J. Phys. D: Condens. Matter 6 447
[4] ［4］Falub C V, Mijnarends P E, Eijt S W H, van Huis M A, van Veen A, Schut H 2002 Phys. Rev. B 66 075426
[5] ［5］Chen X L, Kong W, Weng H M, Ye B J 2008 Acta Phys. Sin. 57 3271 (in Chinese) ［陈祥磊、孔伟、翁惠民、叶邦角 2008 57 3271］
[6] ［6］Chen X L, Xi C Y, Ye B J, Weng H M 2007 Acta Phys. Sin. 56 6695 (in Chinese) ［陈祥磊、郗传英、叶邦角、翁惠民 2007 56 6695］
[7] ［7］Jensen K O 1989 J. Phys. D: Condens. Matter 1 10595
[8] ［8］Puska M J, Nieminen R M 1983 J. Phys. F: Met. Phys. 13
[9] ［9］Plazaola F, Seitsonent A P, Puska M J 1994 J. Phys. D: Condens. Matter 6 8809
[10] ］Boronski E, Nieminen R M 1986 Phys. Rev. B 34 3820
[11] ］Barbiellini B, Puska M J, Korhonen T, Harju A, Torsti T, Nieminen R M 1996 Phys. Rev. B 53 16201
[12] ］Liu R H, Wu G, Wu T, Fang D F, Chen H, Li S Y, Xie Y L, Wang X F, Yang R L, Ding L, He C, Feng D L, Chen X H 2008 Phys. Rev. Lett. 101 087001
[13] ］Liu L H, Dong C, Deng D M, Chen Z P, Zhang J C 2001 Acta Phys. Sin. 50 769 (in Chinese) ［刘丽华、董成、邓冬梅、陈镇平、张金仓 2001 50 769］
[14] ］Chen Z P, Zhang J C, Cao G X, Cao S X 2002 Acta Phys. Sin. 51 2150 (in Chinese) ［陈镇平、张金仓、曹桂新、曹世勋 2002 51 2150］
[15]
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