Publications by Maja Deborah Bachmann

Layered metals as polarized transparent conductors

Philip Johannes Walter Moll, Matthias Carsten Putzke, Chunyu Guo, Maja Deborah Bachmann

The quest to improve transparent conductors balances two key goals: increasing electrical conductivity and increasing optical transparency. To improve both simultaneously is hindered by the physical limitation that good metals with high electrical conducti ...

Nature Portfolio2023

Crossing the ballistic-ohmic transition via high energy electron irradiation

Philip Johannes Walter Moll, Matthias Carsten Putzke, Maja Deborah Bachmann

The delafossite metal PtCoO2 is among the highest-purity materials known, with low-temperature mean free path up to 5 mu m in the best as-grown single crystals. It exhibits a strongly faceted, nearly hexagonal Fermi surface. This property has profound cons ...

AMER PHYSICAL SOC2023

Controlling superconductivity of CeIrIn5 microstructures by substrate selection

Philip Johannes Walter Moll, Matthias Carsten Putzke, Chunyu Guo, Maja Deborah Bachmann, Maarten Ruud van Delft, Joshua Alan Wolfe Straquadine

Superconductor/metal interfaces are usually fabricated in heterostructures that join these dissimilar materials. A conceptually different approach has recently exploited the strain sensitivity of heavy-fermion superconductors, selectively transforming regi ...

AIP Publishing2022

Scanning SQUID microscopy in a cryogen-free dilution refrigerator

Philip Johannes Walter Moll, Maja Deborah Bachmann

We report a scanning superconducting quantum interference device (SQUID) microscope in a cryogen-free dilution refrigerator with a base temperature at the sample stage of at least 30 mK. The microscope is rigidly mounted to the mixing chamber plate to opti ...

2021

Scale-invariant magnetic anisotropy in RuCl(3)at high magnetic fields

Philip Johannes Walter Moll, Maja Deborah Bachmann

Scale-invariant magnetic anisotropy in RuCl(3)has been revealed through measurements of its magnetotropic coefficient, providing evidence for a high degree of exchange frustration that favours the formation of a spin liquid state. In RuCl3, inelastic neutr ...

2020

Orbital effect and weak localization in the longitudinal magnetoresistance of Weyl semimetals NbP, NbAs, TaP, and TaAs

Philip Johannes Walter Moll, Maja Deborah Bachmann

Weyl semimetals such as the TaAs family (TaAs, TaP, NbAs, NbP) host quasiparticle excitations resemblingthe long-sought-after Weyl fermions at special band-crossing points in the band structure denoted as Weylnodes. They are predicted to exhibit a negative ...

2020

h/e oscillations in interlayer transport of delafossites

Philip Johannes Walter Moll, Matthias Carsten Putzke, Maja Deborah Bachmann

Microstructures can be carefully designed to reveal the quantum phase of the wave-like nature of electrons in a metal. Here, we report phase-coherent oscillations of out-of-plane magnetoresistance in the layered delafossites PdCoO2 and PtCoO2. The oscillat ...

American Association for the Advancement of Science2020

Out-of-plane transport in ZrSiS and ZrSiSe microstructures

Philip Johannes Walter Moll, Maja Deborah Bachmann, Kent Robert Shirer

A recent class of topological nodal-line semimetals with the general formula MSiX (M = Zr, Hf and X = S, Se, Te) has attracted much experimental and theoretical interest due to their properties, particularly their large magnetoresistances and high carrier ...

2019

Spatial control of heavy-fermion superconductivity in CeIrIn5

Philip Johannes Walter Moll, Matthias Carsten Putzke, Maja Deborah Bachmann, Kent Robert Shirer

Although crystals of strongly correlated metals exhibit a diverse set of electronic ground states, few approaches exist for spatially modulating their properties. In this study, we demonstrate disorder-free control, on the micrometer scale, over the superc ...

American Association for the Advancement of Science2019

Persistent antiferromagnetic order in heavily overdoped Ca1-xLaxFeAs2

László Forró, Ana Akrap, Henrik Moodysson Rønnow, Ivica Zivkovic, Sergiy Katrych, Edoardo Martino, Philip Johannes Walter Moll, Maja Deborah Bachmann

In the Ca1-xLaxFeAs2 (1 1 2) family of pnictide superconductors, we have investigated a highly overdoped composition (x = 0.56), prepared by a high-pressure, high-temperature synthesis. Magnetic measurements show an antiferromagnetic transition at T-N = 12 ...

2019

Super-geometric electron focusing on the hexagonal Fermi surface of PdCoO2

Philip Johannes Walter Moll, Matthias Carsten Putzke, Maja Deborah Bachmann

Geometric electron optics may be implemented in solids when electron transport is ballistic on the length scale of a device. Currently, this is realized mainly in 2D materials characterized by circular Fermi surfaces. Here we demonstrate that the nearly pe ...

Nature Research2019

Resonant torsion magnetometry in anisotropic quantum materials

Amelia Emily-Kay Estry, Philip Johannes Walter Moll, Maja Deborah Bachmann, Kent Robert Shirer

Unusual behavior in quantum materials commonly arises from their effective low-dimensional physics, reflecting the underlying anisotropy in the spin and charge degrees of freedom. Here we introduce the magnetotropic coefficient k = partial derivative F-2/p ...

Nature Research2018