Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Zero valley splitting at zero magnetic field for strained Si/SiGe
  quantum wells grown on tilted substrates   The electronic structure for a strained Si/SiGe quantum well grown on a
tilted substrate with periodic steps is calculated using a parameterized
tight-binding method. For a zero tilt angle the energy difference between the
two lowest minima of the conduction band at the center of the Brillouin zone
defines a non-zero valley splitting. At finite tilt angles, the two lowest
conduction band minima shift to k0 and -k0 in the Brillouin zone and have equal
energy. The valley splitting for quantum wells grown on a tilted substrate is
therefore equal to zero, which is a direct consequence of the periodicity of
the steps at the interfaces between the quantum well and the buffer materials.

20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph