University of St Andrews
School of Physics and Astronomy
We are theoretical condensed matter physicists interested in many-body
and interaction effects
in systems that are attractive for future quantum technology.
Our current activities involve:
Topological states by self-organisation transitions in interacting low-dimensional conductors.
New physics achievable with Majorana bound states in condensed matter systems.
Generation and detection of entanglement in nanostructures.
For details on our recent activities click here.
Potential post-doc or PhD applicants: please look here.
Latest papers by the group
Non-Equilibrium Charge Dynamics in Majorana-Josephson Devices
I. J. van Beek, A. Levy Yeyati, B. Braunecker
Phys. Rev. B 98, 224502 (2018)
We investigate the impact of introducing Majorana bound states, formed by a proximitized semiconducting
nanowire in the topological regime, into a current biased capacitive Josephson junction, thereby adding
delocalized states below the superconducting gap. We find that this qualitatively changes the charge
dynamics of the system, diminishing the role of Bloch oscillations and causing single-particle tunneling
effects to dominate. We fully characterize the resulting charge dynamics and the associated voltage and
current signals. Our work reveals a rich landscape of behaviors in both the static and time-varying
driving modes. This can be directly attributed to the presence of Majorana bound states, which serve as
a pathway for charge transport and enable nonequilibrium excitations of the Majorana-Josephson device.
Kinetic Stabilization of 1D Surface States near Twin Boundaries in Noncentrosymmetric BiPd
C. M. Yim, C. Trainer, A. Maldonado, B. Braunecker, A. Yaresko, D. C. Peets, P. Wahl
Phys. Rev. Lett. 121, 206401 (2018)
The search for one-dimensional (1D) topologically protected electronic states has become an important research goal for
condensed matter physics owing to their potential use in spintronic devices or as a building block for topologically
nontrivial electronic states. Using low temperature scanning tunneling microscopy, we demonstrate the formation of 1D
electronic states at twin boundaries at the surface of the noncentrosymmetric material BiPd. These twin boundaries are
topological defects that separate regions with antiparallel orientations of the crystallographic b axis. We demonstrate
that the formation of the 1D electronic states can be rationalized by a change in effective mass of two-dimensional
surface states across the twin boundary. Our work therefore reveals a novel route towards designing 1D electronic states
with strong spin-orbit coupling.