hello
my name is trained freedom one i'm looking at the university of cambridge and today
i want to tell you what is interesting about our electronic structure studies on the
fisher wrote into silicon two
it sounds like a rather export a combination of elements but it is actually a
member of a very broad family of materials including the are make taxable conductors and
have experiment material
now if we don't want to know the properties of a metal we need to
know it's crystal structure and we usually to use this from x ray diffraction measurements
the other important bit is the electronic structure and here quantum oscillation measurements are very
powerful pro
so now we have you met investigated with use "'em" road young to silicon two
which is have that mturk and all
crystal structure we know it's lattice parameters from x ray diffraction but there's one thing
one missing power meter
namely position of the silicon atoms within the unit so it's that this that position
of this so they can atoms
so we've done
high resolution single crystal structure refinement to find the silicon position and we perform numerical
that israel excitation calculations to find the minimal energy
corresponding a silicon position they both agree that are well and finally we could use
quantum oscillations to prove that this the like and that position is right
this is possible because the electronic structure and in particular the from a service depends
very sensitively on the second that position
as a result we obtain a very precise knowledge about the lattice structure fiftysome wrote
into silicon two and he obtained a very precise knowledge about its electronic structure
in particular we know that is this got these two from a sophistry
so one of the implications
first
we know that the whole the fact shows a very justine to bend behavior and
having proving that there are two from is to fit sheets
and having measure then will allow for a very detailed
description of the whole the fact and all that electronic transport properties
more generally
we have found that this summer stuff as topology depends very sensitively on the silly
kinds that position and this is very common to the whole family of materials
for the i'm take tides it's the iron thousand are an angle which is equivalent
to the silicon that position and in the i don't think tied it determines the
magnetic and superconducting purpose it properties of the material
finally the feast and wrote into silicon two is an idea reference component to determine
wrote them to select into it has got
same structure same that just parameters even this that position of the silicon atoms is
the same
but there's one difference that element has one electron lesson it's for f show
and it is this what electron missing which determines all the interesting properties of a
tableau doomed to so they can to
i like transform one band very close to the filming energy which hybrid eyes is
why they can't affect with the connection electrons and thereby forms a re normalized that
this we normalize spent has a much larger
for me weight vector
constituting a large from a surface
the system wrote into silicon to has a full for actual lying well be though
the frame energy and b are left with only the connection electrons in that sense
it represents a small from a surface reference to that of remote into silicon two
we can now take the measurements on the system wrote into is like into and
compare them to those done previously on the travel wrote into silicon two
we find very different angular dependencies of the observed quantum oscillations
and therefore we can rule out if small for mischievous configuration for the tableau them
to so that kinda
as a conclusion our measurements highlight the prisons of the large from a surface in
it or converging to select and