@article{56267,
  author       = {{Serino, Laura and Ridder, Werner and Bhattacharjee, Abhinandan and Gil López, Jano and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{2837-6714}},
  journal      = {{Optica Quantum}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Orchestrating time and color: a programmable source of high-dimensional entanglement}}},
  doi          = {{10.1364/opticaq.532334}},
  year         = {{2024}},
}

@article{51356,
  abstract     = {{<jats:title>Abstract</jats:title>
               <jats:p>Lithium niobate has emerged as a promising platform for integrated quantum optics, enabling efficient generation, manipulation, and detection of quantum states of light. However, integrating single-photon detectors requires cryogenic operating temperatures, since the best performing detectors are based on narrow superconducting wires. While previous studies have demonstrated the operation of quantum light sources and electro-optic modulators in LiNbO<jats:sub>3</jats:sub> at cryogenic temperatures, the thermal transition between room temperature and cryogenic conditions introduces additional effects that can significantly influence device performance. In this paper, we investigate the generation of pyroelectric charges and their impact on the optical properties of lithium niobate waveguides when changing from room temperature to 25 K, and vice versa. We measure the generated pyroelectric charge flow and correlate this with fast changes in the birefringence acquired through the Sénarmont-method. Both electrical and optical influence of the pyroelectric effect occur predominantly at temperatures above 100 K.</jats:p>}},
  author       = {{Thiele, Frederik and Hummel, Thomas and Lange, Nina Amelie and Dreher, Felix and Protte, Maximilian and Bruch, Felix vom and Lengeling, Sebastian and Herrmann, Harald and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
  issn         = {{2633-4356}},
  journal      = {{Materials for Quantum Technology}},
  keywords     = {{General Earth and Planetary Sciences, General Environmental Science}},
  number       = {{1}},
  publisher    = {{IOP Publishing}},
  title        = {{{Pyroelectric influence on lithium niobate during the thermal transition for cryogenic integrated photonics}}},
  doi          = {{10.1088/2633-4356/ad207d}},
  volume       = {{4}},
  year         = {{2024}},
}

@article{63219,
  abstract     = {{<jats:p>We introduce the framework of Bayesian relative belief that directly evaluates whether or not the experimental data at hand support a given hypothesis regarding a quantum system by directly comparing the prior and posterior probabilities for the hypothesis. In model-dimension certification tasks, we show that the relative-belief procedure typically chooses Hilbert spaces that are never smaller in dimension than those selected from optimizing a broad class of information criteria, including Akaike's criterion. As a concrete and focused exposition of this powerful evidence-based technique, we apply the relative-belief procedure to an important application: . In particular, just by comparing prior and posterior probabilities based on data, we demonstrate its capability of tracking multiphoton emissions using (realistically lossy) single-photon detectors in order to assess the actual quality of photon sources without making  assumptions, thereby reliably safeguarding source integrity for general quantum-information and communication tasks with Bayesian reasoning. Finally, we discuss how relative belief can be exploited to carry out parametric model certification and estimate the total dimension of the quantum state for the combined (measured) physical and interacting external systems described by the Tavis-Cummings model.</jats:p>
          <jats:sec>
            <jats:title/>
            <jats:supplementary-material>
              <jats:permissions>
                <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
                <jats:copyright-year>2024</jats:copyright-year>
              </jats:permissions>
            </jats:supplementary-material>
          </jats:sec>}},
  author       = {{Teo, Y. S. and Shringarpure, S. U. and Jeong, H. and Prasannan, Nidhin and Brecht, Benjamin and Silberhorn, Christine and Evans, M. and Mogilevtsev, D. and Sánchez-Soto, L. L.}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  number       = {{1}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Relative-belief inference in quantum information theory}}},
  doi          = {{10.1103/physreva.110.012231}},
  volume       = {{110}},
  year         = {{2024}},
}

@article{63216,
  abstract     = {{<jats:p>The characterization of the complex spectral amplitude, that is, the spectrum and spectral phase, of single-photon-level light fields is a crucial capability for modern photonic quantum technologies. Since established pulse characterization techniques are not applicable at low intensities, alternative approaches are required. Here, we demonstrate the retrieval of the complex spectral amplitude of single-photon-level light pulses through measuring their chronocyclic <jats:italic toggle="yes">Q</jats:italic> −function. Our approach draws inspiration from quantum state tomography by exploiting the analogy between quadrature phase space and time-frequency phase space. In the experiment, we perform time-frequency projections with a quantum pulse gate (QPG), which directly yield the chronocyclic <jats:italic toggle="yes">Q</jats:italic> −function. We evaluate the complex spectral amplitude from the measured chronocyclic <jats:italic toggle="yes">Q</jats:italic> −function data with maximum likelihood estimation (MLE), which is the established technique for quantum state tomography. The MLE yields not only an unambigious estimate of the complex spectral amplitude of the state under test that does not require any <jats:italic toggle="yes">a priori</jats:italic> information, but also allows for, in principle, estimating the spectral-temporal coherence properties of the state. Our method accurately recovers features such as jumps in the spectral phase and is resistant against regions with zero spectral intensity, which makes it immediately beneficial for classical pulse characterization problems.</jats:p>}},
  author       = {{Bhattacharjee, Abhinandan and Folge, Patrick Fabian and Serino, Laura Maria and Řeháček, Jaroslav and Hradil, Zdeněk and Silberhorn, Christine and Brecht, Benjamin}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{3}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Pulse characterization at the single-photon level through chronocyclic <i>Q</i>-function measurements}}},
  doi          = {{10.1364/oe.540125}},
  volume       = {{33}},
  year         = {{2024}},
}

@article{63220,
  abstract     = {{<jats:p>Identifying a reasonably small Hilbert space that completely describes an unknown quantum state is crucial for efficient quantum information processing. We introduce a general dimension-certification protocol for both discrete and continuous variables that is fully evidence based, relying solely on the experimental data collected and no other unjustified assumptions whatsoever. Using the Bayesian concept of relative belief, we take the effective dimension of the state as the smallest one such that the posterior probability is larger than the prior, as dictated by the data. The posterior probabilities associated with the relative-belief ratios measure the strength of the evidence provide by these ratios so that we can assess whether there is weak or strong evidence in favor or against a particular dimension. Using experimental data from spectral-temporal and polarimetry measurements, we demonstrate how to correctly assign Bayesian plausible error bars for the obtained effective dimensions. This makes relative belief a conservative and easy-to-use model-selection method for any experiment.</jats:p>
          <jats:sec>
            <jats:title/>
            <jats:supplementary-material>
              <jats:permissions>
                <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
                <jats:copyright-year>2024</jats:copyright-year>
              </jats:permissions>
            </jats:supplementary-material>
          </jats:sec>}},
  author       = {{Teo, Y. S. and Shringarpure, S. U. and Jeong, H. and Prasannan, Nidhin and Brecht, Benjamin and Silberhorn, Christine and Evans, M. and Mogilevtsev, D. and Sánchez-Soto, L. L.}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  number       = {{5}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Evidence-Based Certification of Quantum Dimensions}}},
  doi          = {{10.1103/physrevlett.133.050204}},
  volume       = {{133}},
  year         = {{2024}},
}

@article{54288,
  abstract     = {{<jats:p>The ability to apply user-chosen large-scale unitary operations with high fidelity to a quantum state is key to realizing future photonic quantum technologies. Here, we realize the implementation of programmable unitary operations on up to 64 frequency-bin modes. To benchmark the performance of our system, we probe different quantum walk unitary operations, in particular, Grover walks on four-dimensional hypercubes with similarities exceeding 95% and quantum walks with 400 steps on circles and finite lines with similarities of 98%. Our results open a path toward implementing high-quality unitary operations, which can form the basis for applications in complex tasks, such as Gaussian boson sampling.</jats:p>
          <jats:sec>
            <jats:title/>
            <jats:supplementary-material>
              <jats:permissions>
                <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
                <jats:copyright-year>2024</jats:copyright-year>
              </jats:permissions>
            </jats:supplementary-material>
          </jats:sec>}},
  author       = {{De, Syamsundar and Ansari, Vahid and Sperling, Jan and Barkhofen, Sonja and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  number       = {{2}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Realization of high-fidelity unitary operations on up to 64 frequency bins}}},
  doi          = {{10.1103/physrevresearch.6.l022040}},
  volume       = {{6}},
  year         = {{2024}},
}

@article{63218,
  abstract     = {{<jats:p>Linear optical quantum networks, consisting of a quantum input state and a multiport interferometer, are an important building block for many quantum technological concepts, e.g., Gaussian boson sampling. Here, we propose the implementation of such networks based on frequency conversion by utilizing a so-called multioutput quantum pulse gate (MQPG). This approach allows the resource-efficient and therefore scalable implementation of frequency-bin-based, fully programmable interferometers in a single spatial and polarization mode. Quantum input states for this network can be provided by utilizing the strong frequency entanglement of a type-0 parametric down-conversion (PDC) source. Here, we develop a theoretical framework to describe linear networks based on an MQPG and PDC and utilize it to investigate the limits and scalabilty of our approach.</jats:p>
          <jats:sec>
            <jats:title/>
            <jats:supplementary-material>
              <jats:permissions>
                <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
                <jats:copyright-year>2024</jats:copyright-year>
              </jats:permissions>
            </jats:supplementary-material>
          </jats:sec>}},
  author       = {{Folge, Patrick Fabian and Stefszky, Michael and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{2691-3399}},
  journal      = {{PRX Quantum}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{A Framework for Fully Programmable Frequency-Encoded Quantum Networks Harnessing Multioutput Quantum Pulse Gates}}},
  doi          = {{10.1103/prxquantum.5.040329}},
  volume       = {{5}},
  year         = {{2024}},
}

@article{63217,
  abstract     = {{<jats:p>We demonstrate a high-dimensional mode-sorter for single photons based on a multi-output quantum pulse gate, which we can program to switch between different temporal-mode encodings including pulse modes, frequency bins, time bins, and their superpositions. This device can facilitate practical realizations of quantum information applications such as high-dimensional quantum key distribution and thus enables secure communication with enhanced information capacity. We characterize the mode-sorter through a detector tomography in 3 and 5 dimensions and find a fidelity up to 0.958 ± 0.030 at the single-photon level.</jats:p>}},
  author       = {{Serino, Laura Maria and Eigner, Christof and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{3}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Programmable time-frequency mode-sorting of single photons with a multi-output quantum pulse gate}}},
  doi          = {{10.1364/oe.544206}},
  volume       = {{33}},
  year         = {{2024}},
}

@article{54815,
  abstract     = {{<jats:p>Broadband quantum light is a vital resource for quantum metrology and spectroscopy applications such as quantum optical coherence tomography or entangled two photon absorption. For entangled two photon absorption in particular, very high photon flux combined with high time-frequency entanglement is crucial for observing a signal. So far these conditions could be met by using high power lasers driving degenerate, type 0 bulk-crystal spontaneous parametric down conversion (SPDC) sources. This naturally limits the available wavelength ranges and precludes deterministic splitting of the generated output photons. In this work we demonstrate an integrated two-colour SPDC source utilising a group-velocity matched lithium niobate waveguide, reaching both exceptional brightness 1.52⋅10<jats:sup>6</jats:sup>pairssmWGHz and large bandwidth (7.8 THz FWHM) while pumped with a few mW of continuous wave (CW) laser light. By converting a narrow band pump to broadband pulses the created photon pairs show correlation times of Δ<jats:italic>τ</jats:italic> ≈ 120 fs while maintaining the narrow bandwidth Δ<jats:italic>ω</jats:italic><jats:sub>
      <jats:italic>p</jats:italic>
    </jats:sub> ≪ 1 MHz of the CW pump light, yielding strong time-frequency entanglement. Furthermore our process can be adapted to a wide range of central wavelengths.</jats:p>}},
  author       = {{Pollmann, René and Roeder, Franz and Quiring, Victor and Ricken, Raimund and Eigner, Christof and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{14}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Integrated, bright broadband, two-colour parametric down-conversion source}}},
  doi          = {{10.1364/oe.522549}},
  volume       = {{32}},
  year         = {{2024}},
}

@article{57862,
  abstract     = {{The latest applications in ultrafast quantum metrology require bright, broadband bi-photon sources with one of the photons in the mid-infrared and the other in the visible to near infrared. However, existing sources based on bulk crystals are limited in brightness due to the short interaction length and only allow for limited dispersion engineering. Here, we present an integrated PDC source based on a Ti:LiNbO3 waveguide that generates broadband bi-photons with central wavelengths at 860 nm and 2800 nm. Their spectral bandwidth exceeds 25 THz and is achieved by simultaneous matching of the group velocities (GVs) and cancellation of GV dispersion for the signal and idler field. We provide an intuitive understanding of the process by studying our source’s behavior at different temperatures and pump wavelengths, which agrees well with simulations.}},
  author       = {{Roeder, Franz and Gnanavel, Abira and Pollmann, René and Brecht, Olga and Stefszky, Michael and Padberg, Laura and Eigner, Christof and Silberhorn, Christine and Brecht, Benjamin}},
  issn         = {{1367-2630}},
  journal      = {{New Journal of Physics}},
  number       = {{12}},
  publisher    = {{IOP Publishing}},
  title        = {{{Ultra-broadband non-degenerate guided-wave bi-photon source in the near and mid-infrared}}},
  doi          = {{10.1088/1367-2630/ad9f98}},
  volume       = {{26}},
  year         = {{2024}},
}

@article{57028,
  abstract     = {{<jats:p>Lithium niobate and lithium tantalate are among the most widespread materials for nonlinear, integrated photonics. Mixed crystals with arbitrary Nb–Ta ratios provide an additional degree of freedom to not only tune materials properties, such as the birefringence but also leverage the advantages of the singular compounds, for example, by combining the thermal stability of lithium tantalate with the larger nonlinear or piezoelectric constants of lithium niobate. Periodic poling allows to achieve phase-matching independent of waveguide geometry and is, therefore, one of the commonly used methods in integrated nonlinear optics. For mixed crystals, periodic poling has been challenging so far due to the lack of homogeneous, mono-domain crystals, which severely inhibit domain growth and nucleation. In this work, we investigate surface-near (&amp;lt;1μm depth) domain inversion on x-cut lithium niobate tantalate mixed crystals via electric field poling and lithographically structured electrodes. We find that naturally occurring head-to-head or tail-to-tail domain walls in the as-grown crystal inhibit domain inversion at a larger scale. However, periodic poling is possible if the gap size between the poling electrodes is of the same order of magnitude or smaller than the average size of naturally occurring domains. This work provides the basis for the nonlinear optical application of lithium niobate tantalate mixed crystals.</jats:p>}},
  author       = {{Bollmers, Laura and Babai-Hemati, Tobias and Koppitz, Boris and Eigner, Christof and Padberg, Laura and Rüsing, Michael and Eng, Lukas M. and Silberhorn, Christine}},
  issn         = {{0003-6951}},
  journal      = {{Applied Physics Letters}},
  number       = {{15}},
  publisher    = {{AIP Publishing}},
  title        = {{{Surface-near domain engineering in multi-domain x-cut lithium niobate tantalate mixed crystals}}},
  doi          = {{10.1063/5.0210972}},
  volume       = {{125}},
  year         = {{2024}},
}

@inproceedings{57107,
  author       = {{Kress, Christian and Schwabe, Tobias and Mihaylov, Martin Miroslavov and Silberhorn, Christine and Scheytt, J. Christoph}},
  location     = {{Paderborn}},
  title        = {{{Integrated Pulse Generator for Photon Pair Generation using Lithium Niobate on Insulator Technology}}},
  year         = {{2024}},
}

@misc{57089,
  author       = {{Kruse, Stephan and Brecht, Benjamin and Silberhorn, Christine and Serino, Laura Maria}},
  title        = {{{Quantenoptisch-unterstütztes Sende-/Empfangssystem}}},
  year         = {{2024}},
}

@article{57619,
  abstract     = {{<jats:p>Ferroelectric liquid crystals exhibiting a chiral smectic C* phase are deposited on z cut periodically poled lithium niobate substrates and investigated by polarized optical microscopy. While the pure substrates placed between crossed polarizers and observed in transmission appear dark, uniformly aligned liquid crystal films deposited on these substrates show alternating domains with varying brightness. This effect can be attributed to the well-known coupling between the direction of the spontaneous polarization and the optical axis in the birefringent ferroelectric smectic C* phase. Quantitative measurements of the tilt angle between the local optical axis and the smectic layer normal confirm antiparallel orientations of spontaneous polarization of the liquid crystal from domain to domain, as expected by the periodic poling of the lithium niobate substrate. This effect provides a valuable non-destructive method of optical inspection of the quality of periodically poled ferroelectric substrates, which plays an important role in achieving quasi-phase-matching in non-linear optical applications.</jats:p>}},
  author       = {{Meier, Patrick A. and Keuker-Baumann, Susanne and Röder, Thorsten and Herrmann, Harald and Ricken, Raimund and Silberhorn, Christine and Kitzerow, Heinz-Siegfried}},
  issn         = {{1896-3757}},
  journal      = {{Opto-Electronics Review}},
  pages        = {{150611--150611}},
  publisher    = {{Polish Academy of Sciences Chancellery}},
  title        = {{{Optical imaging of ferroelectric domains in periodically poled lithium niobate using ferroelectric liquid crystals}}},
  doi          = {{10.24425/opelre.2024.150611}},
  year         = {{2024}},
}

@article{57743,
  author       = {{Krishnaswamy, Suchitra and Schlue, Fabian and Ares, L. and Dyachuk, V. and Stefszky, Michael and Brecht, Benjamin and Silberhorn, Christine and Sperling, Jan}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  number       = {{2}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Experimental retrieval of photon statistics from click detection}}},
  doi          = {{10.1103/physreva.110.023717}},
  volume       = {{110}},
  year         = {{2024}},
}

@inproceedings{57108,
  author       = {{Kruse, Stephan and Brecht, Benjamin and Silberhorn, Christine}},
  title        = {{{A Quantum Pulse Gate Enhanced Photonic Radar Architecture }}},
  doi          = {{10.5281/zenodo.14934743}},
  year         = {{2024}},
}

@article{59269,
  abstract     = {{Ferroelectric materials play a crucial role in a broad range of technologies due to their unique properties that are deeply connected to the pattern and behavior of their ferroelectric (FE) domains. Chief among them, barium titanate (BaTiO3; BTO) sees widespread applications such as in electronics but equally is a ferroelectric model system for fundamental research, e.g., to study the interplay of such FE domains, the domain walls (DWs), and their macroscopic properties, owed to BTO’s multiple and experimentally accessible phase transitions. Here, we employ Second Harmonic Generation Microscopy (SHGM) to in situ investigate the cubic-to-tetragonal (at ∼126°C) and the tetragonal-to-orthorhombic (at ∼5°C) phase transition in single-crystalline BTO via three-dimensional (3D) DW mapping. We demonstrate that SHGM imaging provides the direct visualization of FE domain switching as well as the domain dynamics in 3D, shedding light on the interplay of the domain structure and phase transition. These results allow us to extract the different transition temperatures locally, to unveil the hysteresis behavior, and to determine the type of phase transition at play (first/second order) from the recorded SHGM data. The capabilities of SHGM in uncovering these crucial phenomena can easily be applied to other ferroelectrics to provide new possibilities for in situ engineering of advanced ferroic devices.}},
  author       = {{Kirbus, Benjamin and Seddon, Samuel D. and Kiseleva, Iuliia and Beyreuther, Elke and Rüsing, Michael and Eng, Lukas M.}},
  issn         = {{0021-8979}},
  journal      = {{Journal of Applied Physics}},
  number       = {{15}},
  publisher    = {{AIP Publishing}},
  title        = {{{Probing ferroelectric phase transitions in barium titanate single crystals via in-situ second harmonic generation microscopy}}},
  doi          = {{10.1063/5.0237769}},
  volume       = {{136}},
  year         = {{2024}},
}

@article{59271,
  abstract     = {{Lithium niobate (LNO) and lithium tantalate (LTO) see widespread use in fundamental research and commercial technologies reaching from electronics over classical optics to integrated quantum communication. The mixed crystal system lithium niobate tantalate (LNT) allows for the dedicate engineering of material properties by combining the advantages of the two parental materials LNO and LTO. Vibrational spectroscopies such as Raman spectroscopy or (Fourier transform) infrared (IR) spectroscopy are vital techniques to provide detailed insight into the material properties, which is central to the analysis and optimization of devices. This work presents a joint experimental–theoretical approach allowing to unambiguously assign the spectral features in the LNT material family through both Raman and IR spectroscopy, as well as providing an in‐depth explanation for the observed scattering efficiencies based on first‐principles calculations. The phononic contribution to the static dielectric tensor is calculated from the experimental and theoretical data using the generalized Lyddane–Sachs–Teller relation and compared with the results of the first‐principles calculations.}},
  author       = {{Bernhardt, Felix and Gharat, Soham and Kapp, Alexander and Pfeiffer, Florian and Buschbeck, Robin and Hempel, Franz and Pashkin, Oleksiy and Kehr, Susanne C. and Rüsing, Michael and Sanna, Simone and Eng, Lukas M.}},
  issn         = {{1862-6300}},
  journal      = {{physica status solidi (a)}},
  number       = {{1}},
  pages        = {{2300968}},
  publisher    = {{Wiley}},
  title        = {{{Lattice Dynamics of LiNb(1–x)Ta(x)O3 Solid Solutions: Theory and Experiment}}},
  doi          = {{10.1002/pssa.202300968}},
  volume       = {{222}},
  year         = {{2024}},
}

@article{59270,
  abstract     = {{Lithium niobate tantalate (LiNb1−xTaxO3, LNT) solid solutions offer exciting new possibilities for applications ranging from optics, piezotronics, and electronics beyond the capabilities of the widely used singular compounds of lithium niobate (LiNbO3, LN) or lithium tantalate (LiTaO3, LT). Crystal growth of homogeneous LNT single crystals by the Czochralski method is still challenging. One key aspect of homogeneous growth is the accurate knowledge of thermal conductivity through the crystal boule during the growth, which is central to control the crystal growth. Therefore, the temperature dependent thermal conductivity of pure LN, LT, and LNT solid solutions, as well as of selected doped LN and LT crystals (Mg, Zn) was investigated across the temperature range from 300 to 1300 K. The results that span across the whole composition range can directly be applied for optimizing growth conditions of both LNT solid solutions as well as doped and undoped LN and LT crystals.}},
  author       = {{Bashir, Umar and Rüsing, Michael and Klimm, Detlef and Blukis, Roberts and Koppitz, Boris and Eng, Lukas M. and Bickermann, Matthias and Ganschow, Steffen}},
  issn         = {{0925-8388}},
  journal      = {{Journal of Alloys and Compounds}},
  publisher    = {{Elsevier BV}},
  title        = {{{Thermal conductivity in solid solutions of lithium niobate tantalate single crystals from 300 K up to 1300 K}}},
  doi          = {{10.1016/j.jallcom.2024.176549}},
  volume       = {{1008}},
  year         = {{2024}},
}

@article{59272,
  abstract     = {{Ferroelectrics such as LiNbO3 (LN) are wide-band-gap insulators that may show a high local electric conductivity at the domain walls (DWs). The latter are interfaces separating regions of noncollinear polarization, which can be manipulated to build integrated nanoelectronic elements. In the present work, we model different DW types in LN from first principles. Our models reveal the DW morphology and shed light on their electronic properties: A strong band bending is predicted for charged DWs, leading to local metallicity. Defect trapping at the DW may further enhance the electric conductivity.}},
  author       = {{Verhoff, Leonard M. and Pionteck, Mike N. and Rüsing, Michael and Fritze, Holger and Eng, Lukas M. and Sanna, Simone}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Two-dimensional electronic conductivity in insulating ferroelectrics: Peculiar properties of domain walls}}},
  doi          = {{10.1103/physrevresearch.6.l042015}},
  volume       = {{6}},
  year         = {{2024}},
}