Question

Which four member of the <111> family of directions lie in a plane that is parallel to the (110) plane? Make clear sketches of all your work to get full credit. Useful protocol to locate plane: Algorithm for determining the Miller Indices of a plane 1. If plane passes through selected origin, establish a new origin in another unit cell 2. Read off values of intercepts of plane designated A, B, C) with x, y, and z axes in terms of a, b, o 3. Take reciprocals of intercepts 4. Normalize reciprocals of intercepts by multiplying by lattice parameters a, b, and 4. Reduce to smallest integer values 5. Enclose resulting Miller Indices in parentheses, no commas i.e., (hkl)

Answer 1

Step-by-step explanation:

The <111> family of directions includes four directions: <111>, <1-1-1>, <11-2>, and <1-12>.

To find the planes parallel to the (110) plane, we need to use the Miller Indices of the (110) plane, which are (1 1 0).

Using the algorithm for determining Miller Indices of a plane:

We can choose any point on the plane, but for simplicity, let's choose the origin.

The plane intercepts the x, y, and z axes at (1,0,0), (0,1,0), and (0,0,1), respectively, since it passes through the points (0,0,0) and (1,1,0).

Taking the reciprocals of these intercepts, we get (1/1, 1/1, 1/0) = (1, 1, ∞).

Normalizing by multiplying by the lattice parameters a, b, and c, we get (a, b, ∞). Since we do not know the value of c, we cannot normalize the third index.

To reduce to smallest integer values, we take the reciprocals of the indices and multiply by a common factor to get integers. Since the third index is infinity, we can ignore it. Taking the reciprocals of the first two indices, we get (1/1, 1/1, 1/1/2) = (1, 1, 2).

Enclosing the indices in parentheses, we get the Miller Indices of the (110) plane: (1 1 0).

Now, to find the planes parallel to the (110) plane, we need to find the directions that are perpendicular to the (110) plane. We know that the normal vector to the (110) plane is <1 1 0>, so any direction that is perpendicular to this vector will lie in a plane parallel to the (110) plane.

The four <111> family directions that are perpendicular to <1 1 0> are <11-2>, <1-12>, <-112>, and <-1-1-2>. These four directions lie in a plane that is parallel to the (110) plane.

Note that <111> and <1-1-1> do not lie in a plane parallel to the (110) plane.