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Here a recently observed weak first order transition in doped SrTiO3 is argued to be a consequence of the coupling between strain and order parameter fluctuations. Starting with a semi-microscopic action, and using renormalization group…

统计力学 · 物理学 2015-05-13 Nabyendu Das

Equilibrium statistical physics is applied to layered neural networks with differentiable activation functions. A first analysis of off-line learning in soft-committee machines with a finite number (K) of hidden units learning a perfectly…

无序系统与神经网络 · 物理学 2009-10-31 M. Biehl , E. Schloesser , M. Ahr

SrTiO$_3$ is an incipient ferroelectric on the verge of a polar instability, which is avoided at low temperatures by quantum fluctuations. Within this unusual quantum paraelectric phase, superconductivity persists despite extremely dilute…

超导电性 · 物理学 2019-09-12 Ryan Russell , Noah Ratcliff , Kaveh Ahadi , Lianyang Dong , Susanne Stemmer , John W. Harter

The structural phase transition in hexagonal BaMnO$_3$ occurring at $T_c$=130 K was studied in ceramic samples using electron and X-ray diffraction, second harmonic generation as well as by dielectric and lattice dynamic spectroscopies. The…

The advances of machine-learned force fields have opened up molecular dynamics (MD) simulations for compounds for which ab-initio MD is too resource-intensive and phenomena for which classical force fields are insufficient. Here we describe…

材料科学 · 物理学 2024-08-07 Sebastian Bichelmaier , Jesús Carrete , Georg K. H. Madsen

The accurate prediction of solid-solid structural phase transitions at finite temperature is a challenging task, since the dynamics is so slow that direct simulations of the phase transitions by first-principles (FP) methods are typically…

材料科学 · 物理学 2021-05-25 Peitao Liu , Carla Verdi , Ferenc Karsai , Georg Kresse

Over the years, the Self-Consistent Harmonic Approximation (SCHA) has been successfully utilized to determine the transition temperature of many different magnetic models, particularly the Berezinskii-Thouless-Kosterlitz transition in…

强关联电子 · 物理学 2023-09-20 A. R. Moura

A first-principles study of the vibrational modes of PbTiO_3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone (BZ). The calculations use the local-density approximation and…

mtrl-th · 物理学 2009-10-30 Alberto Garcia , David Vanderbilt

The discovery of very large piezo- and pyroelectric effects in ZrO2 and HfO2-based thin films opens up new opportunities to develop silicon-compatible sensor and actor devices. The effects are amplified close to the polar-orthorhombic to…

Machine-learned interatomic potentials enable realistic finite temperature calculations of complex materials properties with first-principles accuracy. It is not yet clear, however, how accurately they describe anharmonic properties, which…

材料科学 · 物理学 2021-10-01 Carla Verdi , Ferenc Karsai , Peitao Liu , Ryosuke Jinnouchi , Georg Kresse

Despite vibrational properties being critical for the ab initio prediction of the finite temperature stability and transport properties of solids, their inclusion in ab initio materials repositories has been hindered by expensive…

Perovskite oxides are known to exhibit many magnetic, electronic and structural phases as function of doping and temperature. These materials are theoretically frequently investigated by the DFT+U method, typically in their ground state…

材料科学 · 物理学 2023-12-12 Thies Jansen , Geert Brocks , Menno Bokdam

Accurately predicting the Curie temperature ($T_c$) of ferroelectrics from first principles remains a major challenge, as theoretical estimates often fall significantly below experimental values. In this work, we investigate the origin of…

材料科学 · 物理学 2026-01-21 Denan Li , Chris Ahart , Shi Liu

We demonstrate that a machine learning technique with a simple feedforward neural network can sensitively detect two successive phase transitions associated with the Berezinskii-Kosterlitz-Thouless (BKT) phase in q-state clock models…

统计力学 · 物理学 2021-08-13 Yusuke Miyajima , Yusuke Murata , Yasuhiro Tanaka , Masahito Mochizuki

Titanium dioxide has been extensively studied in the rutile or anatase phases, while its high-pressure phases are less well understood, despite that many are thought to have interesting optical, mechanical and electrochemical properties.…

材料科学 · 物理学 2022-03-14 Jacob G. Lee , Chris J. Pickard , Bingqing Cheng

Barium titanate (BaTiO$_3$) is a prototypical ferroelectric perovskite that undergoes the rhombohedral-orthorhombic-tetragonal-cubic phase transitions as the temperature increases. In this work, we develop a classical interatomic potential…

材料科学 · 物理学 2016-11-23 Yubo Qi , Shi Liu , Ilya Grinberg , Andrew M. Rappe

SrTiO$_3$ has been extensively investigated owing to its abundant degrees of freedom for modulation. However, the microscopic mechanism of thermal transport especially the relationship between phonon scattering and lattice distortion during…

材料科学 · 物理学 2023-03-15 Jian Han , Changpeng Lin , Ce-wen Nan , Yuan-hua Lin , Ben Xu

Recently, machine learning has emerged as an alternative, powerful approach for predicting quantum-mechanical properties of molecules and solids. Here, using kernel ridge regression and atomic fingerprints representing local environments of…

材料科学 · 物理学 2018-03-08 Teppei Suzuki , Ryo Tamura , Tsuyoshi Miyazaki

Accurately predicting carrier mobility in strongly anharmonic solids necessitates a precise characterization of lattice dyndamics as a function of temperature. We achieve consistency with experimental electron mobility data for bulk…

We study the recently discovered even-odd effects in the normal state of single-electron devices manufactured at strontium titanium oxide/lanthanum aluminum oxide interfaces (STO/LAO). Within the framework of the number parity-projected…

介观与纳米尺度物理 · 物理学 2020-06-08 Xing Yang , Quanhui Liu , Boldizsár Jankó