MEAM Potential for Si-Ge - Revision history

Xzhang11 at 22:36, 6 March 2017

2017-03-06T22:36:17Z

← Older revision		Revision as of 22:36, 6 March 2017
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	<P ALIGN="CENTER">		<P ALIGN="CENTER">
	<FONT SIZE="+3" color="darkred"><STRONG>		<FONT SIZE="+3" color="darkred"><STRONG>
	MEAM Potential for ~~Au-~~Si</STRONG></font></P>		MEAM Potential for Si-Ge</STRONG></font></P>
	<DIV>		<DIV>
	<P ALIGN="CENTER"><STRONG>Xiaohan Zhang and Wei Cai</STRONG></P>		<P ALIGN="CENTER"><STRONG>Xiaohan Zhang and Wei Cai</STRONG></P>

Xzhang11: /* Cross Potential between Ge and Si */

2017-03-06T22:31:14Z

Cross Potential between Ge and Si

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 The parameters for the cross potential are specified in '''SiGe.meam''' file.  The lines relevant for the cross potential (i.e. between species 1 and 2) are shown below.  The values correspond to Table 1 of G. Grochola et al. / Chemical Physics Letters 493 (2010) 57–60 59.
-lattce(1,2) = b1
+ lattce(1,2) = b1         (<math>C_{\max}</math>)
 The values for  <math>E_c ({\rm AuGe}) = 3.189</math>.

Xzhang11: /* Cross Potential between Ge and Si */

2017-03-06T22:29:02Z

Cross Potential between Ge and Si

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 The parameters for the cross potential are specified in '''SiGe.meam''' file.  The lines relevant for the cross potential (i.e. between species 1 and 2) are shown below.  The values correspond to Table 1 of G. Grochola et al. / Chemical Physics Letters 493 (2010) 57–60 59.
- lattce(1,2) = b1
+re(1,2) = 5.529
- attrac(1,2) = 0.0
+lattce(1,2) = b1
-<math>E_c ({\rm AuSi}) = 0.5*[ E_c ({\rm Au}) + E_c({\rm Si}) ] - {\rm delta}(1,2) = 0.5 * (3.93 + 4.63) - 0.125 = 4.155</math>.
+The values for  <math>E_c ({\rm AuGe}) = 3.189</math>.
-<math>\rho_0^{\rm Si} / \rho_0^{\rm Au}</math> = 1.48 because of the <math>\rho_0^{\rm Si}</math> and <math>\rho_0^{\rm Au}</math> values specified above.
+<math>E_c ({\rm AuGe}) = 0.5*[ E_c ({\rm Au}) + E_c({\rm Ge}) ] - {\rm delta}(1,2) = 0.5 * (3.93 + 3.85) - 0.071 = 3.819</math>.
 Cmax = 2.8 is the default value.

Xzhang11: /* Benchmark in MD++ */

2017-03-06T22:06:19Z

Benchmark in MD++

← Older revision		Revision as of 22:06, 6 March 2017
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	==Benchmark in MD++==		==Benchmark in MD++==

	Compile the code using the following command.		Compile the code using the following command on mc2.

	make meam-lammps build=R SYS=~~gpp~~		make meam-lammps build=R SYS=mc2_mpich

	Use the following command to compute the ~~equilibrium~~ ~~lattice constant and cohesive energy~~ of pure Au ~~(FCC).~~ ~~You can download the [[media:si-au~~.~~tcl~~.~~txt \| si-au~~.~~tcl]]~~ ~~from the link.~~		Use the following command to compute the melting point of pure Si, Ge, and Si0.5Ge0.5.

	bin/meam-lammps_gpp scripts/work/si_au/si_au_benchmark.tcl 1		bin/meam-lammps_gpp scripts/work/si_au/si_au_benchmark.tcl 1

Xzhang11: /* Cross Potential between Ge and Si */

2017-03-06T22:04:29Z

Cross Potential between Ge and Si

← Older revision		Revision as of 22:04, 6 March 2017
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	==Cross Potential between Ge and Si==		==Cross Potential between Ge and Si==

	The parameters for the cross potential are specified in '''~~AuSi2nn~~.meam''' file. The lines relevant for the cross potential (i.e. between species 1 and 2) are shown below. The values correspond to Table 3 of ~~Ryu~~ ~~and~~ ~~Cai,~~ J. ~~Phys.~~ ~~Condens.~~ ~~Matter,~~ ~~22,~~ ~~055401~~ (2010).		The parameters for the cross potential are specified in '''SiGe.meam''' file. The lines relevant for the cross potential (i.e. between species 1 and 2) are shown below. The values correspond to Table 1 of G. Grochola et al. / Chemical Physics Letters 493 (2010) 57–60 59.

	re(1,2) = 2.700 (<math>r_e</math>)		re(1,2) = 2.700 (<math>r_e</math>)

Xzhang11: /* MEAM Potential for Ge */

2017-03-06T22:02:39Z

MEAM Potential for Ge

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 Note that  the nearest neighbor distance <math> R_i^0 </math> = '''alat'''  <math>\times \sqrt{3}/4</math> for the diamond cubic structure.
 <math>\rho_0^{\rm Si}</math> = '''rozero''' will be important only for cross-potential.
 ==Cross Potential between Ge and Si==

Xzhang11: /* MEAM Potential for Ge */

2017-03-06T22:02:10Z

MEAM Potential for Ge

← Older revision		Revision as of 22:02, 6 March 2017
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	===MEAM Potential for Ge===		===MEAM Potential for Ge===
	We use the '~~Ge5~~' potential whose parameters are originally given in M. I. Baskes, The main parameters in the MEAM potential are specified in the meamf file. (In MD++, this file is in the potentials/MEAMDATA folder.) The lines corresponding to 'Ge5' are given below. Most of these parameters correspond to Table III of Baskes PRB (1992), as shown below.		We use the 'Ge' potential whose parameters are originally given in M. I. Baskes, The main parameters in the MEAM potential are specified in the meamf file. (In MD++, this file is in the potentials/MEAMDATA folder.) The lines corresponding to 'Ge5' are given below. Most of these parameters correspond to Table III of Baskes PRB (1992), as shown below.

	<math>\alpha_i</math> <math>\beta_i^{(0)}</math> <math>\beta_i^{(1)}</math> <math>\beta_i^{(2)}</math> <math>\beta_i^{(3)}</math>		<math>\alpha_i</math> <math>\beta_i^{(0)}</math> <math>\beta_i^{(1)}</math> <math>\beta_i^{(2)}</math> <math>\beta_i^{(3)}</math>
	elt lat z ielement atwt alpha b0 b1 b2 b3		elt lat z ielement atwt alpha b0 b1 b2 b3
	'~~Si4~~' 'dia' 4. 14 28.~~086~~ 4.87 4.4 5.5 5.5 5.5		'Ge' 'dia' 4. 32 72.64 4.98 4.55 5.5 5.5 5.5


	<math>(R_i^0)</math> <math>E_i^0</math> <math>A_i</math> <math>t_i^{(0)}</math> <math>t_i^{(1)}</math> <math>t_i^{(2)}</math> <math>t_i^{(3)}</math> <math>\rho_0^{\rm Si}</math>		<math>(R_i^0)</math> <math>E_i^0</math> <math>A_i</math> <math>t_i^{(0)}</math> <math>t_i^{(1)}</math> <math>t_i^{(2)}</math> <math>t_i^{(3)}</math> <math>\rho_0^{\rm Si}</math>
	alat esub asub t0 t1 t2 t3 rozero ibar		alat esub asub t0 t1 t2 t3 rozero ibar
	5.~~431~~ 4.63 1. 1.0 3.13 4.47 -1.8 1.48 0		5.6575 3.85 1. 1.0 4.02 5.23 -1.6 1.35 0

	Note that the nearest neighbor distance <math> R_i^0 </math> = '''alat''' <math>\times \sqrt{3}/4</math> for the diamond cubic structure.		Note that the nearest neighbor distance <math> R_i^0 </math> = '''alat''' <math>\times \sqrt{3}/4</math> for the diamond cubic structure.

Xzhang11: /* MEAM Potential for Ge */

2017-03-06T22:00:13Z

MEAM Potential for Ge

← Older revision		Revision as of 22:00, 6 March 2017
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	===MEAM Potential for Ge===		===MEAM Potential for Ge===
		⚫	We use the 'Ge5' potential whose parameters are originally given in M. I. Baskes, The main parameters in the MEAM potential are specified in the meamf file. (In MD++, this file is in the potentials/MEAMDATA folder.) The lines corresponding to 'Ge5' are given below. Most of these parameters correspond to Table III of Baskes PRB (1992), as shown below.

	We use the 'Si4' potential whose parameters are originally given in M. I. Baskes, Phys. Rev. B 46, 2727 (1992), and later modified by Ryu and Cai, J. Phys. Condens. Matter 22, 055401 (2010).

⚫	The main parameters in the MEAM potential is specified in the ~~'''~~meamf~~'''~~ file. (In MD++, this file is in the potentials/MEAMDATA folder.) The lines ~~correspond~~ to '~~Siz~~' is given below. Most of these parameters correspond to Table III of Baskes PRB (1992), as shown below.

	<math>\alpha_i</math> <math>\beta_i^{(0)}</math> <math>\beta_i^{(1)}</math> <math>\beta_i^{(2)}</math> <math>\beta_i^{(3)}</math>		<math>\alpha_i</math> <math>\beta_i^{(0)}</math> <math>\beta_i^{(1)}</math> <math>\beta_i^{(2)}</math> <math>\beta_i^{(3)}</math>

Xzhang11: /* MEAM Potential for Si */

2017-03-06T21:58:55Z

MEAM Potential for Si

← Older revision		Revision as of 21:58, 6 March 2017
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	'''ibar''' is a setting used in the equation of state (EOS), and will be explained later.		'''ibar''' is a setting used in the equation of state (EOS), and will be explained later.

	The modification made in Ryu and Cai JPCM (2010) is specified in the '''AuSi2nn.meam''' file. The variables in Eq.(A.1) of Ryu and Cai JPCM (2010) are given in the parenthesis.

	erose_form = 3
	rc = 4.5
	attrac(2,2) = -0.36 (<math>\gamma</math>)
	repuls(2,2) = 16.0 (<math>\lambda</math>)
	Cmin(2,2,2) = 1.85 (<math>C_{\rm min}</math>)

	Note that we label the atomic species of Si as 2.

	===MEAM Potential for Ge===		===MEAM Potential for Ge===

Xzhang11: /* MEAM Potential for Si */

2017-03-06T21:58:25Z

MEAM Potential for Si

← Older revision		Revision as of 21:58, 6 March 2017
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	Note that the nearest neighbor distance <math> R_i^0 </math> = '''alat''' <math>\times \sqrt{3}/4</math> for the diamond cubic structure.		Note that the nearest neighbor distance <math> R_i^0 </math> = '''alat''' <math>\times \sqrt{3}/4</math> for the diamond cubic structure.

	<math>\rho_0^{\rm Si}</math> = '''rozero''' will be important only for cross-potential.		<math>\rho_0^{\rm Si}</math> = '''rozero''' will be important only for cross-potential. And note that this is the only different from Si4 line.

	'''ibar''' is a setting used in the equation of state (EOS), and will be explained later.		'''ibar''' is a setting used in the equation of state (EOS), and will be explained later.