It is anyway a lot easier to simulate a solid that has no defects. But many properties found that way turn up in defect-ridden, real materials too. A truly per

It is anyway a lot easier to simulate a solid that has no defects. But many properties found that way turn up in defect-ridden, real materials too. A truly periodic substrate lets you wrap it in a closed universe just big enough for what you hope to make live in it.