Elements with 4f or 5f electrons in unfilled electron bands and their componuds , which have ions carrying magnetic moments but do not magnetically order, or only do so at very low temperatures, are generally known as heavy-fermion or heavy electron systems because the scattering of the conduction electrons with the magnetic ions results in […]
Condensed matter • Materials • Physics • Quantum physics • Theoretical physics
We all know what an insulator is, don’t we? An insulator is any substance that is a poor conductor of heat and electricity. Both properties ussually occur as a consequence of a lack of mobile electrons.If we want to dive a little deeper into the nature of insulators we make use of energy band theory […]
For a successful application in spintronics of any material, a key problem is to get a reliable control of the electronic spin within it. An ideal candidate for this purpose would be any material which is non-magnetic in the bulk but has a tunable ferromagnetic surface layer with a large splitting of the spin-up and […]
Computer science • Mathematics • Mechanical Engineering • Robotics
One thing is designing an object in a computer, and another, quite different, is producing it as a real 3D object. All other things being equal, in general the more curves the designed object has, the more difficult it is to produce. Mathematics can be very helpful in this task. The geometric modeling of a […]
If a nucleus has a nonzero spin, it behaves as a small magnet. Therefore, in an external magnetic field, the nuclear magnetic moment vector precesses about the field direction but only certain otientations are allowed by quantum rules. Thus, for hydrogen (spin 1/2) there are two possible states in the presence of a field, each […]
The scattering of conduction electrons in metals owing to impurities with magnetic moments is known as the Kondo effect, after Jun Kondo, who analysed the phenomenon in 1964. This scattering increases the electrical resistance and has the consequence that, in contrast to ordinary metals, the resistance reaches a minimum as the temperature is lowered and […]
Many aromatic compounds can be made into organic semiconductors by doping them with a substance such as iodine, thereby producing mobile carriers of electric charge. This is analogous to the doping of silicon in an ordinary semiconductor. The benefits of using organic compounds are evident, namely, the resources are available everywhere, extremely cheap, and there […]
Last February I published my first scientific article as principal author in Physical Review B . This article summarizes a big part of my work as a PhD student, a journey that has not been easy. The first version was sent to the journal a year ago; in between many things happened: new experiments, discussions […]
Since the discovery of graphene, a wide diversity of atomic-layer-thick, two-dimensional (2D) materials with varied properties have emerged. Of particular interest are those that exhibit semiconducting behavior, such as hexagonal boron nitride (hBN). hBN is isoelectronic to graphene and has also a honeycomb lattice formed by alternating nitrogen and boron atoms, but in contrast to […]
The computer metaphor draws an analogy between the mind as software and the brain as hardware. In this metaphor, the focus of discussions is usually on the software part, taking for granted that the brain, or the whole nervous system, is a computer of sorts. But this is something that needs to be proved first […]