Related papers: Multipolar magnetism in $5d^2$ vacancy-ordered hal…
Double perovskite-based magnets wherein frustration and competition between emergent degrees of freedom are at play can lead to novel electronic and magnetic phenomena. Herein, we report the electronic structure and magnetic properties of…
We have performed a comprehensive, first-principles high-throughput study of the magnetic properties of halide double perovskites, $Cs_2BB^\prime Cl_6$, with magnetic ions occupying one or both B and B$^\prime$ sites. Our findings indicate…
Recent experiments have discovered multipolar orders in a variety of $d$-orbital Mott insulators. Motivated by uncovering the exchange interactions which underlie octupolar order proposed in the osmate double perovskites, we study a…
Localized $5d^2$ electrons in a cubic crystal field possess multipoles such as electric quadrupoles and magnetic octupoles. We studied the cubic double perovskite Ba$_2$CaOsO$_6$ containing the Os$^{6+}$ ($5d^2$) ions, which exhibits a…
Conflicting interpretations of experimental data preclude the understanding of the quantum magnetic state of spin-orbit coupled $d^2$ double perovskites. Whether the ground state is a Janh-Teller-distorted order of quadrupoles or the…
The subtle interplay between spin-orbit coupling, exchange interactions, and cation ordering can lead to exotic magnetic states in transition-metal ions. We report a comprehensive study of the Re-based (5$d^1$) ordered double perovskite…
We consider strongly spin-orbit coupled double perovskites A$_2$BB'O$_6$ with B' magnetic ions in either $d^1$ or $d^2$ electronic configuration and non-magnetic B ions. We provide insights into several experimental puzzles, such as the…
We investigate how doping-induced small polarons impact the low-temperature multipolar orders of the $5d^2$ double perovskite Ba$_2$CaOsO$_6$. By computing intersite exchange interactions between 5d$^1$ localized hole polarons and 5d$^2$…
In a cubic environment, the ground state of spin-orbit coupled $5d^2$ ions is a non-Kramers $E_g$ doublet, which hosts quadrupole and octupole moments. A series of $5d^2$ osmium double perovskites Ba$_2M$OsO$_6$ (M = Mg, Ca, Zn, Cd) have…
Quantum magnets with spin $J=2$, which arise in spin-orbit coupled Mott insulators, can potentially display multipolar orders. We carry out an exact diagonalization study of a simple octahedral crystal field Hamiltonian for two electrons,…
We report time-of-flight neutron spectroscopic and diffraction studies of the 5$d^2$ cubic double pervoskite magnets, Ba$_2$MOsO$_6$ ($M$ = Zn, Mg, Ca). These cubic materials are all described by antiferromagnetically-coupled 5$d^2$…
We examine the role of charge, structural, and spin degrees of freedom in the previously poorly understood phase transition in the 5$d^1$ transition-metal double perovskite Cs$_2$TaCl$_6$, using a combination of computational and…
Magnetic structures and the relationship between spin and charge-orbital orderings of an A-site ordered double-perovskite manganite SmBaMn2O6, an anticipated multiferroic material, were investigated by means of neutron diffraction. The spin…
Double-perovskite oxides that contain both 3d and 5d transition metal elements have attracted growing interest as they provide a model system to study the interplay of strong electron interaction and large spin-orbit coupling (SOC). Here,…
Double perovskite compounds containing 5d transition metal elements have been extensively studied as platforms for multipolar order phenomena stemming from spin-orbit-entangled 5d electrons. In this study, we examine the interplay between…
Motivated by the time-reversal symmetry breaking signal in muon spin relaxation below a transition temperature without accompanying noticeable magnetic Bragg peaks in $5d^2$ Os double perovskites, a rare ferro-octupolar order was proposed…
In electronic solids with strong spin-orbit interactions (SOIs), the spin and orbital degrees of freedom of an electron are quantum mechanically entangled, which may result in an exotic multipolar order instead of a conventional dipolar…
We develop a microscopic theory of multipole interactions and orderings in 5$d^2$ transition metal ion compounds. In a cubic environment, the ground state of 5$d^2$ ions is a non-Kramers $E_g$ doublet, which is nonmagnetic but hosts…
"Hidden"-order phases with high-rank multipolar order parameters have been recently detected in several cubic double perovskites of 5$d$ transition metals. Here, by constructing and solving an ab initio low-energy Hamiltonian, we show that…
The coexistence of the strongly correlated 3$d$ transition metal (TM) atom and the strong spin-orbit coupling (SOC) of 5$d$ TM atom is potential to host exotic physical phenomena. In the present work, we have studied the magnetism resulting…