Quantum matter in high magnetic fields

Research group

Research theme

Sub department

About

Signatures of a Quantum Griffiths Phase close to an Electronic Nematic Quantum Phase Transition

(2021)

Authors:

Pascal Reiss, David Graf, Amir A Haghighirad, Thomas Vojta, Amalia I Coldea
More details from the publisher

Angular Modulations in Magnetic Torque Induced by Phase Transitions in the Triangular Supersolid $2H$-AgNiO$_2$

ArXiv 2609.28445 (2026)

Authors:

John S Pearce, Zeyu Ma, Alimamy Bangura, Timo Sorgel, Martin Jansen, Radu Coldea, Amalia I Coldea
Details from ArXiV

Field-induced incipient spin-density phase stabilized inside the nematic phase of FeSe$_{1-x}$S$_x$

ArXiv 2609.28446 (2026)

Authors:

I Paulescu, RM Abedin, JS Pearce, WH Fong, Z Zajicek, A Morfoot, W Knafo, O Squire, D Graf, AA Haghighirad, AI Coldea
Details from ArXiV

TabPFN-3.5: Technical Report

ArXiv 2609.17895 (2026)

Authors:

Benjamin Jäger, Nick Erickson, Léo Grinsztajn, Felix Birkel, Klemens Flöge, Oscar Key, Kürşat Kaya, Jonas Kübler, Adèle Frankel, Tobias Schröder, Anurag Garg, Jan Hendrik Metzen, David Salinas, Simon Bing, Kristina Collins, Tuana Çelik, Vahid Balazadeh, Lydia Sidhoum, Tomás Pereda, Brendan Roof, Andrej Tschalzev, Siyuan Guo, Philipp Singer, Lennart Purucker, Jake Robertson, Marie Salmon, Philipp Jund, Jerry Chen, Diana Kriuchkova, Arthur Cahu, Eliott Kalfon, Adrian Hayler, Georg Grab, Vitor Monteiro, Lilly Wehrhahn, Dominik Safaric, Clara Cornu, Alan Arazi, Rylee Grace, Simone Alessi, Mihir Manium, Bernhard Schölkopf, Yann LeCun, Madelon Hulsebos, Sauraj Gambhir, Noah Hollmann, Frank Hutter
Details from ArXiV

Engineering Local Polar Frustration in Lead‐Free Dielectric Ceramics for Ultrahigh Normalized Energy Storage Performance

Advanced Functional Materials Wiley 36:76 (2026) e77848

Authors:

Hareem Zubairi, Muhammad Wasim, Songhao Fu, Xiaojiao Liu, Annette K Kleppe, Zhilun Lu, Antonio Feteira, Diming Xu, Joseph CA Prentice, Ge Wang

Abstract:

ABSTRACT Lead‐free dielectric capacitors require high‐recoverable energy density and thermal stability under low operating fields to prevent premature breakdown. Here, we demonstrate a design strategy for high‐performance lead‐free dielectrics based on two key principles: selecting a highly polarizable ferroelectric matrix and engineering local polar frustration to suppress long‐range order and stabilize an ergodic relaxer state. Using the (0.94Na 0.5 Bi 0.5 TiO 3 ‐0.06BaTiO 3 )–x(0.85NaNbO 3 ‐0.15CaTiO 3 ) (NBT‐BT‐NN‐CT) as an exemplar in this work, structural analyses reveal that NN‐CT incorporation induces a frustrated polar structure characterized by the nanoscale coexistence of rhombohedral, tetragonal, and cubic‐polymorphs. Density functional theory confirms that energetic degeneracy physically prevents the formation of stable macro‐domains. The optimal composition yields wide temperature stability (±15% permittivity up to 370°C), far exceeding the X7R industrial standard, delivering a recoverable energy density of >5 J cm −3 under low field (250 kV cm −1 ) achieving an ultrahigh normalized energy density (W a ) of >0.020 mC cm −2 , 60% improvement over conventional NBT‐based counterparts in the literature (e.g., 0.012–0.015 mC cm −2 ). Furthermore, in situ synchrotron X‐ray diffraction (<160 kV cm −1 ) provides strong crystallographic evidence of this dynamic structural stability, confirming the absence of irreversible field‐induced phase transitions. These results establish polar frustration engineering as a transferable design principle for resilient, high‐performance lead‐free dielectrics.
More details from the publisher
More details