MagDot Participant No.6 MagDot Participant No.6 Institute of - PowerPoint PPT Presentation

MagDot Participant No.6 MagDot Participant No.6 Institute of Physics, Academy of Sciences of the Czech Republic Na Slovance 2, Prague 8, Czech Republic http://www.fzu.cz www.fzu.cz http:// Principal Investigator: Miroslav Kotrla Principal Investigator: Theoretical Department, IPASCR kotrla (at) fzu.cz

Early Stage of MBE and PLD Growth in Fe/Mo System  IPASCR &  IPASCR & MagDot MagDot  subm mode  mode submo onolayer growth nolayer growth, , MBE MBE and and PLD PLD – Fe/Mo(110) /Mo(110): experiments and model for : experiments and model for KMC – Fe KMC simulations simulations – results for results for island density vs. temperature island density vs. temperature – – comparison comparison: : MBE MBE vs. vs. PLD – PLD  morfology  morfology of islands grown on BCC( on BCC(110 110): MBE ): MBE of islands grown – realistic realistic model model of Fe of Fe/Mo(110) system /Mo(110) system – – dependence of dependence of island shapes island shapes on T and interactions – on T and interactions  conclusion  conclusion 12.5.2009 Third MagDot Workshop - Napa 2

Participation of IPASCR in MagDot MagDot Participation of IPASCR in Currently involved people: Currently involved people: • • Miroslav Kotrla – – Principal Investigator Miroslav Kotrla Principal Investigator • • Martin Ma Maší šín n - researcher Martin - researcher • • postdoc (D. Goykolov Goykolov) since ) since Oc Oct to ober ber 2007 postdoc (D. 2007 of Mathematical & Physical of • • Ond ř Ond ř ej ej Maršá Mar šálek lek - - graduate student graduate student Mathematical & Physical Faculty of Charles University, Prague Faculty of Charles University, Prague info on SimNANO Wiki http://simnano.fzu.cz/ Project MetHet External: External: Sebastian Weber - University of Wuezburg S. Weber et al., J. Phys.: Cond. Matt. 20, 265004 (2008) growth of strained alloys

Participation of IPASCR in MagDot MagDot Participation of IPASCR in atomistic modeling of initial stages atomistic modeling of initial stages Task: Task: of growth – of growth – submonolayer submonolayer growth rowth Method: Method: kinetic Monte Carlo (KMC) kinetic Monte Carlo (KMC) Formally: Formally: workpackage wo rkpackage 2 – – real ealist stic Kinet ic Kinetic Monte Car c Monte Carlo Early stage of This workshop: This workshop: MBE and PLD growth in Fe/ Mo system

Submonolayer growth growth Submonolayer Θ  1 ML Coverage: Observed quantity: Density of islands N Succession of regimes:   nucleation nucleation   aggregation aggregation   coalescence coalescence Importance: Importance: (i) the formation of Methods of study surface features experimental: STM, AFM (ii) measurements of thery: KMC, rate equations surface diffusion Third MagDot Workshop - - Napa Napa 5 Third MagDot Workshop 5

Evolution of island density Evolution of island density Ag/ Pt(111) Ag/ Pt(111) a) 0.0024 ML a) 0.0024 ML b) 0.006 ML b) 0.006 ML c) 0.03 ML c) 0.03 ML d) 0.06 ML d) 0.06 ML There is an interval of coverage with saturated island density H.Brune et al. PRL 73 , (1994) 1955 H.Brune et al. PRL 73 , (1994) 1955 Third MagDot Workshop - - Napa Napa 6 Third MagDot Workshop 6

Arrhenius plot for saturated Arrhenius plot for saturated island density island density   N exp -E /k T ฀ S D B Ag/Pt(111) E D E can be estimated from can be estimated from D an experimental data Ag/Ag/Pt(111) an experimental data H. Brune Brune et al. PRB. 52 (1995) R 14380. H. et al. PRB. 52 (1995) R 14380 Ag/Ag(111) Third MagDot Workshop - - Napa Napa 7 Third MagDot Workshop 7

Two modes of growth: MBE – Molecular beam epitaxy PLD – Pulsed laser deposition MBE - - extensively studied in the past MBE extensively studied in the past PLD – – new additional parameters PLD new additional parameters , etc. f , etc. pulse repetition rate f pulse repetition rate some references on PLD: some references on PLD: MagDot MagDot P.O Jubert, O. Fruchart, and C. Meyer Surface Science 522 (2003) 8. H. Hinnenmann et al. PRL. 87 (2001) 135701. Unusual Scaling for PLD Unusual Scaling for PLD nucleation density nucleation density in PLD depends on in PLD depends on intensity I of pulses intensity I of pulses 12.5.2009 Third MagDot Workshop - Napa 8

Pulsed laser deposition of Fe on Mo(110) experiment experiment P.O Jubert, O. Fruchart, and C. Meyer Surface Science 522 (2003) 8. nucleation density N x nucleation density N x vs. . temperature temperature vs 12.5.2009 Third MagDot Workshop - Napa 9

Shape of Fe islands in Fe/Mo(110) grown by MBE M. B . Bod ode et al. e et al. J. Prokop et al. M J. Prokop et al. PRL L (2004 2004) ) 067201 067201. PRB 73 (2006 2006) ) 014428 014428. PR 2 ( PRB 73 ( 92 9 12.5.2009 Third MagDot Workshop - Napa 10

Microscopic KMC model Microscopic KMC model   a solid- -on on- -solid model solid model a solid   random deposition with flux F random deposition with flux F   diffusion: jump to n.n n.n. position with . position with diffusion: jump to the rate the rate      R k exp - E /k T , E E nE 0 D B D d b E , E , k Material parameters: d b 0 Control parameters: F, T Third MagDot Workshop - - Napa Napa 11 Third MagDot Workshop 11

Microscopic KMC model Microscopic KMC model   a solid- -on on- -solid model solid model a solid   random deposition with flux F random deposition with flux F   diffusion: jump to n.n n.n. position with . position with diffusion: jump to the rate the rate      R k exp - E /k T , E E nE 0 D B D d b E , E , k Material parameters: d b 0 Control parameters: F, T Third MagDot Workshop - - Napa Napa 12 Third MagDot Workshop 12

How to to get get material material parameters parameters? ? How a) a) fitting experimental data fitting experimental data b) b) first irst principle calculation f principle calculation Parameters for KMC simulations of Fe/Mo(110) P.O Jubert, O. Fruchart, and C. Meyer Surface Science 522 (2003) 8. kinetic analysis of experiment performed but special character - pulsed laser deposition (PLD) considered DFT calculation of Mark Asta Third MagDot Workshop - - Napa Napa 13 Third MagDot Workshop 13

Parameters for KMC KMC simulations of Fe/Mo(110) simulations of Fe/Mo(110) Parameters for     X Y E ? E ? E ? k ? d b b 0 two sets used: a) a) Jubert et al. Jubert et al.      11 E 0 . 1 0 . 05 , k 8 10 eV Hz d 0 X Y E E and varied b b b) b) Mark Asta Asta Mark   E 0 . 41 , E 0 . 33 eV eV d b   12 k 4 10 Hz 0 Third MagDot Workshop - - Napa Napa 14 Third MagDot Workshop 14

Configurations of islands for different temperatures in MBE mode T = 200 K T = 200 K T = 300 K T = 300 K T = 400 K T = 400 K 12.5.2009 Third MagDot Workshop - Napa 15

Configurations of islands for different temperatures in MBE mode T = 200 K T = 200 K T = 300 K T = 300 K T = 400 K T = 400 K 12.5.2009 Third MagDot Workshop - Napa 16

Configurations for MBE and PLD ( ( θ θ = 0.1) ) = 0.1 PLD , PLD , PLD PLD MBE , MBE , E E = 0.60 eV eV , E E = 0.33 33 eV eV = 0.60 = 0. , E E = 0.60 eV eV = 0.60 b b b b b b T = 400 K T = 400 K T = 400 K T = 400 K T = 400 K T = 400 K T = 500 K T = 500 K T = 500 K T = 500 K T = 500 K T = 500 K 12.5.2009 Third MagDot Workshop - Napa 17

Island density N x as function of the inverse temperature P.-O. Jubert, O. Fruchart, and C. Meyer Surface Sci. 522 (2003), 8 12.5.2009 Third MagDot Workshop - Napa 18

Island density N x as function of the inverse temperature P.-O. Jubert, O. Fruchart, and C. Meyer Surface Sci. 522 (2003), 8 12.5.2009 Third MagDot Workshop - Napa 19

Pulsed laser deposition vs. MBE 12.5.2009 Third MagDot Workshop - Napa 20

Pulsed laser deposition vs. MBE continued MBEvsPLD.png 12.5.2009 Third MagDot Workshop - Napa 21

Early stage of MBE and PLD Growth in Fe/Mo System  IPASCR &  IPASCR & MagDot MagDot  subm mode  mode submo onolayer growth nolayer growth, , MBE MBE and and PLD PLD – Fe/Mo(110) /Mo(110): experiments and model for : experiments and model for KMC – Fe KMC simulations simulations – results for results for island density vs. temperature island density vs. temperature – – comparison comparison: : MBE MBE vs. vs. PLD – PLD  morfology  morfology of islands grown on BCC( on BCC(110 110): MBE ): MBE of islands grown – realistic realistic model model of Fe of Fe/Mo(110) system /Mo(110) system – – dependence of dependence of island shapes island shapes on T and interactions – on T and interactions  conclusion  conclusion 12.5.2009 Third MagDot Workshop - Napa 22