lattice style scale keyword values ...-
The lattice style must be consistent with the dimension of the simulation - see the dimension command. Styles sc -or bcc or fcc or diamond are for 3d problems. Styles sq or -sq2 or hex are for 2d problems. Style custom can be used for -either 2d or 3d problems. +or bcc or fcc or hcp or diamond are for 3d problems. Styles +sq or sq2 or hex are for 2d problems. Style custom can be +used for either 2d or 3d problems.
A lattice consists of a unit cell, a set of basis atoms within that cell, and a set of transformation parameters (scale, origin, orient) @@ -89,22 +89,24 @@ minimum volume.
Lattices of style sc, fcc, bcc, and diamond are 3d lattices that define a cubic unit cell with edge length = 1.0. This means a1 = -1.0 0.0 0.0, a2 = 0.0 1.0 0.0, and a3 = 0.0 0.0 1.0. The placement of -the basis atoms within the unit cell are described in any solid-state -physics text. A sc lattice has 1 basis atom at the -lower-left-bottom corner of the cube. A bcc lattice has 2 basis -atoms, one at the corner and one at the center of the cube. A fcc -lattice has 4 basis atoms, one at the corner and 3 at the cube face -centers. A diamond lattice has 8 basis atoms. +1 0 0, a2 = 0 1 0, and a3 = 0 0 1. Style hcp has a1 = 1 0 0, a2 = 0 +sqrt(3) 0, and a3 = 0 0 sqrt(8/3). The placement of the basis atoms +within the unit cell are described in any solid-state physics text. A +sc lattice has 1 basis atom at the lower-left-bottom corner of the +cube. A bcc lattice has 2 basis atoms, one at the corner and one at +the center of the cube. A fcc lattice has 4 basis atoms, one at the +corner and 3 at the cube face centers. A hcp lattice has 4 basis +atoms, two in the z = 0 plane and 2 in the z = 0.5 plane. A diamond +lattice has 8 basis atoms.
Lattices of style sq and sq2 are 2d lattices that define a square -unit cell with edge length = 1.0. This means a1 = 1.0 0.0 0.0 and a2 -= 0.0 1.0 0.0. A sq lattice has 1 basis atom at the lower-left -corner of the square. A sq2 lattice has 2 basis atoms, one at the -corner and one at the center of the square. A hex style is also a -2d lattice, but the unit cell is rectangular, with a1 = 1.0 0.0 0.0 -and a2 = 0.0 sqrt(3.0) 0.0. It has 2 basis atoms, one at the corner -and one at the center of the rectangle. +unit cell with edge length = 1.0. This means a1 = 1 0 0 and a2 = 0 1 +0. A sq lattice has 1 basis atom at the lower-left corner of the +square. A sq2 lattice has 2 basis atoms, one at the corner and one +at the center of the square. A hex style is also a 2d lattice, but +the unit cell is rectangular, with a1 = 1 0 0 and a2 = 0 sqrt(3) 0. +It has 2 basis atoms, one at the corner and one at the center of the +rectangle.
A lattice of style custom allows you to specify a1, a2, a3, and a list of basis atoms to put in the unit cell. By default, a1,a2,a3 are diff --git a/doc/lattice.txt b/doc/lattice.txt index 2a0686e327..b2bd103a2a 100644 --- a/doc/lattice.txt +++ b/doc/lattice.txt @@ -12,7 +12,7 @@ lattice command :h3 lattice style scale keyword values ... :pre -style = {none} or {sc} or {bcc} or {fcc} or {diamond} or \ +style = {none} or {sc} or {bcc} or {fcc} or {hcp} or {diamond} or \ {sq} or {sq2} or {hex} or {custom} :ulb,l scale = scale factor between lattice and simulation box :l for style {none}: @@ -65,9 +65,9 @@ underlying problem geometry is atoms on a lattice. The lattice style must be consistent with the dimension of the simulation - see the "dimension"_dimension.html command. Styles {sc} -or {bcc} or {fcc} or {diamond} are for 3d problems. Styles {sq} or -{sq2} or {hex} are for 2d problems. Style {custom} can be used for -either 2d or 3d problems. +or {bcc} or {fcc} or {hcp} or {diamond} are for 3d problems. Styles +{sq} or {sq2} or {hex} are for 2d problems. Style {custom} can be +used for either 2d or 3d problems. A lattice consists of a unit cell, a set of basis atoms within that cell, and a set of transformation parameters (scale, origin, orient) @@ -81,22 +81,24 @@ minimum volume. Lattices of style {sc}, {fcc}, {bcc}, and {diamond} are 3d lattices that define a cubic unit cell with edge length = 1.0. This means a1 = -1.0 0.0 0.0, a2 = 0.0 1.0 0.0, and a3 = 0.0 0.0 1.0. The placement of -the basis atoms within the unit cell are described in any solid-state -physics text. A {sc} lattice has 1 basis atom at the -lower-left-bottom corner of the cube. A {bcc} lattice has 2 basis -atoms, one at the corner and one at the center of the cube. A {fcc} -lattice has 4 basis atoms, one at the corner and 3 at the cube face -centers. A {diamond} lattice has 8 basis atoms. +1 0 0, a2 = 0 1 0, and a3 = 0 0 1. Style {hcp} has a1 = 1 0 0, a2 = 0 +sqrt(3) 0, and a3 = 0 0 sqrt(8/3). The placement of the basis atoms +within the unit cell are described in any solid-state physics text. A +{sc} lattice has 1 basis atom at the lower-left-bottom corner of the +cube. A {bcc} lattice has 2 basis atoms, one at the corner and one at +the center of the cube. A {fcc} lattice has 4 basis atoms, one at the +corner and 3 at the cube face centers. A {hcp} lattice has 4 basis +atoms, two in the z = 0 plane and 2 in the z = 0.5 plane. A {diamond} +lattice has 8 basis atoms. Lattices of style {sq} and {sq2} are 2d lattices that define a square -unit cell with edge length = 1.0. This means a1 = 1.0 0.0 0.0 and a2 -= 0.0 1.0 0.0. A {sq} lattice has 1 basis atom at the lower-left -corner of the square. A {sq2} lattice has 2 basis atoms, one at the -corner and one at the center of the square. A {hex} style is also a -2d lattice, but the unit cell is rectangular, with a1 = 1.0 0.0 0.0 -and a2 = 0.0 sqrt(3.0) 0.0. It has 2 basis atoms, one at the corner -and one at the center of the rectangle. +unit cell with edge length = 1.0. This means a1 = 1 0 0 and a2 = 0 1 +0. A {sq} lattice has 1 basis atom at the lower-left corner of the +square. A {sq2} lattice has 2 basis atoms, one at the corner and one +at the center of the square. A {hex} style is also a 2d lattice, but +the unit cell is rectangular, with a1 = 1 0 0 and a2 = 0 sqrt(3) 0. +It has 2 basis atoms, one at the corner and one at the center of the +rectangle. A lattice of style {custom} allows you to specify a1, a2, a3, and a list of basis atoms to put in the unit cell. By default, a1,a2,a3 are