Theoretical physics of condensed matter is one of the
**most progressive** parts of modern physics. The wealth of systems
studied by condensed matter physics provides opportunities for
**fascinating physical phenomena** and open new ways for
**technological innovations**.

# Physics goes quantum

The basic physics of many
phenomena studied by condensed matter physics happens on the atomic scale, where
**quantum properities** of atoms and charge carriers become
important. Thus condensed matter can serve as a real **playground for
quantum-mechanical effects**. With advent of new materials and
technologies the **quatum-relativistic physics** in condesed matter
have become more important. An important manifestation of relativistic behaviour
in condensed matter is coupling of spins and orbital momenta, called
**spin-orbit interaction**. This interactions appears to be
important ingredient for novel materials with possible application in
spintronics.

- Frietsch B., Donges A., Carley R., Teichmann M., Bowlan
J., Döbrich K., Carva K., Legut D., Oppeneer P.M., Nowak U., Weinelt M.,

The role of ultrafast magnon generation in the magnetization dynamics of rare-earth metals.

Science advances, 6(39) (2020)

# Studying new materials

In our group we focus on various
aspects of quantum physics in the solid state of matter. In close collaboration
with experiment we study basic physical properties of novel **functional
materials for spintronics** featuring magnetic moments and/or
spin-orbital interaction. Apart from standard three-dimensional bulk materials
with disorder (like diluted magnetic semiconductors) we study also effects on
interfaces, two-dimensional materials (like graphene), one-dimensional
structures (like quantum wires), and zero-dimensional systems (like quantum
dots). Especially, we focus on **quantum transport** in these
structures, which is of great importance for engineering of novel technical
applications.

- A. Kadlecová, M. Žonda, V. Pokorný and T. Novotný,

Practical guide to quantum phase transitions in quantum-dot-based tunable Josephson junctions,

Physical Review Applied 11, 044094 (2019)

# Proposing new devices

For novel technological
applications, more complex structures need to be proposed and studied. On one
hand side we study magnetotransport through **multilayer
structures** consisted of magnetic layers separated by nonmagnets. These
structures are well know for a possibility of manipulating with their
magnetizations by means of **spin transfer torque**. The effect of
spin transfer torque has a potential for magnetic **random access
memories**. Spin transfer torque acts on magnetic domain wall in single
magnetic layers when electric current flows in the layer's plane. This effect
gives rise to an alternative geometry of magnetic memory known as
**magnetic racetrack memory**.

An important class systems
with quantum-based functionality are **molecular
junctions**.

- F. Evers, R. Korytár, S. Tewari, J. M. van
Ruitenbeek,

Advances and challenges in single-molecule electron transport,

Reviews of Modern Physics 92, 035001 (2020)

# Developing new methods

To study the problems of condensed matter
physics, we use both paper-and-pencil theory as well as numerical calculations.
For studying the basic physical features of materials with atomistic input we
use **ab initio** and **multiscale approaches**. In
our group not only we use accesible numerical software but also develope our
**own numerical codes**.

We apply **machine learning
methods** for the investigation of complex condensed matter
systems.

- J. Arnold, F. Schäfer, M. Žonda and A. U. J. Lode,

Interpretable and unsupervised phase classification,

Phys. Rev. Research 3, 033052, (2021)