Using ab initio calculations, we show that the hidden influence of selection rules on three-phonon scattering can be exposed through anomalous signatures in the pressure ($P$) and temperature ($T$) dependence of the thermal conductivities, $κ$, of certain compounds. Boron phosphide reveals such underlying behavior through an exceptionally sharp initial rise in $κ$ with increasing $P$, which may be the steepest of any material, and also a peak and decrease in $κ$ at high $P$. These features are in stark contrast to the measured behavior for many solids, and occur at experimentally accessible conditions. Similar anomalous behavior is predicted for silicon carbide and other related materials.
Two-dimensional 1H-15N HMBC NMR spectra of a well-known anticonvulsant-carbamazepine-dissolved in chloroform, recorded on an NMR spectrometer and obtained from quantum-chemical calculations prove the existence of hidden conformers in saturated solutions. A weaker influence of ring currents was revealed for the hidden conformation of carbamazepine dissolved in saturated solution, which provides a simple approach for discovering hidden conformations. Hidden conformers were found in three different solvents: dimethyl sulfoxide, chloroform, and dichloromethane.
Observation of robust spin-phonon coupling and indication of hidden structural transition in the spin-driven ferroelectrics Mn4B_2O_9 (B= Nb, Ta)
Center for High Pressure Science and Technology Advanced Research (HPSTAR)（高压科学与技术前沿研究卓越创新中心）；Solid State Physics Division, Bhabha Atomic Research Centre（巴哈原子研究中心固态物理部）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre（巴哈原子研究中心高压与同步辐射物理部）；Shanghai Key Laboratory MFree, Institute for Shanghai Advanced Research in Physical Sciences（上海先进物理科学研究院MFree上海市重点实验室）
Hidden phonon-assisted charge density wave transition in BaFe2Al9 revealed by ultrafast optical spectroscopy
Beijing Normal University（北京师范大学）；Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；University of Chinese Academy of Sciences（中国科学院大学）；Institute of Metal Research, Chinese Academy of Sciences（中国科学院金属研究所）
Phononic enhancement and detection of hidden spin-nematicity and dynamics in quantum magnets
International Center for Quantum Materials, School of Physics, Peking University（北京大学物理学院量子材料国际中心）；Collaborative Innovation Center of Quantum Matter（量子物质协同创新中心）
The representative cuprate, La$_{2-x}$M$_x$CuO$_4$, with M = Sr and $x = 1/8$ is studied via first-principles calculations in the high-temperature tetragonal (HTT), low-temperature orthorhombic (LTO), and low-temperature less-orthorhombic (LTLO) structures. By suppressing the magnetism and superconductivity, the LTLO phase, which has rarely been observed in La$_{2-x}$Sr$_x$CuO$_4$, is found to be the ground state, where the structural phase transitions, HTT$\rightarrow$LTO$\rightarrow$LTLO, can be understood via phonon instability. While the La-O composition is identified to be responsible for…
The phonon dispersion unfolding method is useful for obtaining hidden Bloch symmetries and comparing theoretical results with experiment spectrums (e.g., inelastic neutron scattering, inelastic X-ray scattering, Raman). In this paper, we propose a method to unfold phonon dispersions. The main advantage of this method is the ability to handle systems with heavy breaking of spatial translational symmetry. Its validity is tested by pure diamond, diamond with Si substitution, and diamond with C vacancies.
Revealing Hidden Inversion Symmetry Breaking in ZrTe$_5$ via Phonon-Assisted Heterodyne Amplification
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所凝聚态物理国家实验室）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；International Center for Quantum Materials, School of Physics, Peking University（北京大学物理学院量子材料中心）；Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交通大学汤川研究所）；Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University（上海交通大学张江高等研究院）
Working with epitaxial films of Fe, we succeeded in independent control of different scattering processes in the anomalous Hall effect. The result appropriately accounted for the role of phonons, thereby clearly exposing the fundamental flaws of the standard plot of the anomalous Hall resistivity versus longitudinal resistivity. A new scaling has been thus established that allows an unambiguous identification of the intrinsic Berry curvature mechanism as well as the extrinsic skew scattering and side-jump mechanisms of the anomalous Hall effect.
"Hidden phases" are metastable collective states of matter that are typically not accessible on equilibrium phase diagrams. These phases can host exotic properties in otherwise conventional materials and hence may enable novel functionality and applications, but their discovery and access are still in early stages. Using intense terahertz electric field excitation, we show that an ultrafast phase transition into a hidden ferroelectric phase can be dynamically induced in the quantum paraelectric SrTiO$_3$. The induced lowering in crystal symmetry yields dramatic changes in the phonon excitation…
Recently, we employed electronic polarization-resolved Raman spectroscopy to reveal the strongly correlated excitonic insulator (EI) nature of Ta2NiSe5, Volkov et al. [arXiv:2007.07344], and also showed that for Ta$_2$Ni(Se$_{1-x}$S$_x$)$_5$ alloys the critical excitonic fluctuations diminish with sulfur concentration x exposing a cooperating lattice instability that takes over for large x, Volkov et al. [arXiv:2104.07032]. Here we focus on the lattice dynamics of this EI family. We identify all Raman-active optical phonons of fully symmetric and ac-quadrupole-like symmetries and study their e…
The Cairo tessellation refers to a pattern of type 2 pentagons that can pave an infinite plane without creating a gap or overlap. We reveal the hidden, layered Cairo tessellations in the pyrite structure with a general chemical formula of $AB_2$ and space group $pa\bar3$. We use this hidden tessellation along with density functional theory calculations to examine the possibility of obtaining a two-dimensional (2D) material with the Cairo tessellation from the bulk, using PtP$_2$ as an example. Unlike previously reported single-layer materials such as PdSe$_2$ with a buckled, pentagonal structu…
