Xiao Zheng

Fudan University · Department of Chemistry

Accurate characterization of correlated electronic states, as well as their evolution under external fields or in dissipative environment, is essentially important for understanding the properties of strongly correlated transition‐metal materials involving spin‐unpaired d or f electrons. This paper reviews the development and applications of a nume...

Quantum Brownian motion plays a fundamental role in many areas of modern physics. In the path-integral formulation, environmental fluctuations can be characterized by auxiliary stochastic fields. Intriguingly, for fermionic environments the stochastic fields must be Grassmann valued so as to memorize the order of the random forces exerted on the sy...

Recent technological advancement in scanning tunneling microscope has enabled the measurement of spin-field and spin-spin interactions in single atomic or molecular junctions with an unprecedentedly high resolution. Theoretically, although the fermionic hierarchical equations of motion (HEOM) method has been widely applied to investigate the strong...

Scanning tunneling microscopy (STM) has been utilized to realize the precise measurement and control of local spin states. Experiments have demonstrated that when a nickelocene (Nc) molecule is attached to the apex of an STM tip, the dI/dV spectra exhibit a sharp or a smooth transition when the tip is displaced toward the substrate. However, what l...

Understanding the time evolution of strongly correlated open quantum systems (OQSs) in response to perturbations (quenches) is of fundamental importance to the precise control of quantum devices. It is, however, rather challenging in multi-impurity quantum systems because such evolution often involves multiple intricate dynamical processes. In this...

The integration of scanning tunneling microscopy (STM) and electron spin resonance (ESR) spectroscopy has emerged as a powerful and innovative tool for discerning spin excitations and spin-spin interactions within atoms and molecules adsorbed on surfaces. However, the origin of the STM-ESR signal and the underlying mechanisms that govern the essent...

Non-Markovianity, the intricate dependence of an open quantum system on its temporal evolution history, holds tremendous implications across various scientific disciplines. However, accurately characterizing the complex non-Markovian effects has posed a formidable challenge for numerical simulations. While quantum computing technologies show promis...

Graphene has garnered significant attention due to its unique properties. Among its many intriguing characteristics, the tuning effects induced by adsorbed atoms (adatoms) provide immense potential for the design of graphene-based electronic devices. This work explores the electronic migration in the adatom-graphene composite, using the extended di...

Numerous variational methods have been proposed for solving quantum many-body systems, but they often face exponentially increasing computational complexity as the Hilbert space dimension grows. To address this, we introduce a novel approach using quantum neural networks to simulate the dissipative dynamics of many-body open quantum systems. This m...

Many‐body open quantum systems (OQSs) have a profound impact on various subdisciplines of physics, chemistry, and biology. Thus, the development of a computer program capable of accurately, efficiently, and versatilely simulating many‐body OQSs is highly desirable. In recent years, we have focused on the advancement of numerical algorithms based on...

Electron dynamics driven by few-cycle laser pulses has recently attracted great interest as a means to realizing the manipulation of electron motion on the atomic timescale. Using tight-binding models and the time-dependent nonequilibrium Green's function (TD-NEGF) method, we investigated laser-pulse-induced electron dynamics in armchair graphene n...

One of the most important feature in the Kondo physics is the universal scaling behavior. In this study, we analyze the transport behavior of the spin thermocurrent driven by a small temperature bias and under a weak magnetic field. We conclude that the spin thermocurrent exhibits a universal scaling behavior, similar to the spin susceptibility. Th...

The Peltier effect, which is the reverse counterpart of the Seebeck effect, has been experimentally observed in nanojunctions. Despite its potential applications in cooling nanoelectronic devices, achieving significant figures of merit and cooling power remain challenging. Here, we propose a novel approach to enable substantial Peltier cooling by l...

Many-body open quantum systems (OQS) have a profound impact on various subdisciplines of physics, chemistry, and biology. Thus, the development of a computer program capable of accurately, efficiently, and versatilely simulating many-body OQS is highly desirable. In recent years, we have focused on the advancement of numerical algorithms based on t...

Density functional theory has been widely used in quantum mechanical simulations, but the search for a universal exchange-correlation (XC) functional has been elusive. Over the last two decades, machine-learning techniques have been introduced to approximate the XC functional or potential, and recent advances in deep learning have renewed interest...

The development of heterogeneous asymmetric catalysts has attracted increasing interest in synthetic chemistry but mostly relies on the immobilization of homogeneous chiral catalysts. Herein, a series of chiral metal–organic frameworks (MOFs) have been fabricated by anchoring similar chiral hydroxylated molecules (catalytically inactive) with diffe...

The development of heterogeneous asymmetric catalysts has attracted increasing interest in synthetic chemistry but mostly relies on the immobilization of homogeneous chiral catalysts. Herein, a series of chiral metal‐organic frameworks (MOFs) have been fabricated by anchoring similar chiral hydroxylated molecules (catalytically inactive) with diffe...

Peltier effect is an important thermoelectric phenomenon which stands for the generation of temperature gradient of the interface between two dissimilar conductors by the electric current flowing through them. In this work, we investigate the Peltier effect in serially coupled noninteracting double quantum dot system under a bias voltage. By means...

Single-molecule magnets (SMMs) possess a crucial property called magnetic anisotropy (MA), which has an exceedingly delicate correlation with their structures. In recent years, the study on magneto-structural correlations has emerged as a challenging area in singlemolecule science. Understanding the fundamental physical mechanisms underlying the ma...

In this paper, we present an extended dissipaton equation of motion for studying the dynamics of electronic impurity systems. Compared with the original theoretical formalism, the quadratic couplings are introduced into the Hamiltonian accounting for the interaction between the impurity and its surrounding environment. By exploiting the quadratic f...

Dissipaton theory had been proposed as an exact, nonperturbative approach to deal with open quantum system dynamics, where the influence of the Gaussian environment is characterized by statistical quasi-particles, named dissipatons. In this work, we revisit the dissipaton equation of motion theory and establish an equivalent dissipaton-embedded qua...

Machine learning (ML) has demonstrated its potential usefulness for the development of density functional theory methods. In this work, we construct an ML model to correct the density functional approximations, which adopts semilocal descriptors of electron density and density derivative and is trained by accurate reference data of relative and abs...

In this paper, we present an extended dissipaton equation of motion for studying the dynamics of electronic impurity systems. Compared with the original theoretical formalism, the quadratic couplings are introduced into the Hamiltonian accounting for the interaction between the impurity and its surrounding environment. By exploiting the quadratic d...

Dissipaton theory had been proposed as an exact and nonperturbative approach to deal with open quantum system dynamics, where the influence of Gaussian environment is characterized by statistical quasi-particles named as dissipatons. In this work, we revisit the dissipaton equation of motion theory and establish an equivalent dissipatons-embedded q...

Machine learning (ML) has demonstrated its potential usefulness for the development of density functional theory methods. In this work, we construct an ML model to correct the density functional approximations, which adopts semilocal descriptors of electron density and density derivative and is trained by accurate reference data of relative and abs...

Machine learning (ML) algorithms have shown to be potentially effective in the development of density functional theory (DFT) methods.In this work, we have developed a semilocal ML correction for density functional approximations.The correction adopts simple descriptors of electron density and density derivative, and is trained upon the combination...

The magnetic interactions between the spin-polarized scanning tunnelling microscopy (SP-STM) tip and the localized spin impurities lead to various forms of the Kondo effect. Although these intriguing phenomena enrich Kondo physics, detailed theoretical simulations and explanations are still lacking due to the rather complex formation mechanisms. He...

The exchange–correlation (XC) functional plays the central role in density functional theory (DFT). The exact XC functional determines a unique and universal mapping from the electron density of a system to either the XC potential or the XC energy/energy density. Through a self-consistent way, all properties of the system can be calculated by the m...

Investigations of strongly correlated quantum impurity systems (QIS), which exhibit diversified novel and intriguing quantum phenomena, have become a highly concerning subject in recent years. The hierarchical equations of motion (HEOM) method is one of the most popular numerical methods to characterize QIS linearly coupled to the environment. This...

Magnetic circular dichroism (MCD) is a widely used spectroscopic technique which reveals valuable information about molecular geometry and electronic structure. However, the weak signal and the necessary strong magnets impose major limitations on its application. We propose a novel protocol to overcome these limitations by using pulsed vector beams...

The fermionic hierarchical equations of motion (HEOM) approach has found wide applications in the exploration of open quantum systems, and extensive efforts have been committed to improving its efficiency and accuracy in practical calculations. In this work, by scrutinizing the stationary-state and dynamic properties of Kondo-correlated quantum imp...

Magnetic circular dichroism (MCD) is a widely used spectroscopic technique which reveals valuable information about molecular geometry and electronic structure. However, the weak signal and the necessary strong magnets impose major limitations on its application. We propose a novel protocol to overcome these limitations by using pulsed vector beams...

Here we present a novel stochastic Liouville equation with piecewisely correlated noises, in which the inter-piece correlation is rigorously incorporated by a convolution integral involving functional derivatives. Due to the feature of piecewise correlation, we can perform piecewise ensemble average and serve the average of the preceding interval a...

Electrochemical generation of hydrogen peroxide (H2O2) by two‐electron oxygen reduction offers a green method to mitigate current dependence on the energy‐intensive anthraquinone process, promising its on‐site applications. Unfortunately, in alkaline environments, H2O2 is not stable and undergoes rapid decomposition. Making H2O2 in acidic electroly...

Control of electron dynamics in graphene nanoribbons (GNRs) is critically important for the future applications of graphene-based nanoelectronic devices. Based on real-time simulations, we investigate the manipulation of electronic transport by femtosecond laser pulses in armchair GNRs. The simulation results show that the multiphoton absorption pr...

The fluctuation theorem, where the central quantity is the work distribution, is an important characterization of nonequilibrium thermodynamics. In this work, based on the dissipaton-equation-of-motion theory, we develop an exact method to evaluate the work distributions in quantum impurity system-bath mixing processes, in the presence of non-Marko...

For open quantum systems, environmental dissipative effect can be represented by statistical quasi-particles, namely dissipatons. We exploit this fact to establish the dissipaton thermofield theory. The resulting generalized Langevin dynamics of absorptive and emissive thermofield operators are effectively noise-resolved. The system-bath entangleme...

The electrocatalytic carbon dioxide reduction reaction (CO 2 RR) producing HCOOH and CO is one of the most promising approaches for storing renewable electricity as chemical energy in fuels. SnO 2 is a good catalyst for CO 2 -to-HCOOH or CO 2 -to-CO conversion, with different crystal planes participating the catalytic process. Among them, (110) sur...

In this work, we propose the time-domain Prony fitting decomposition (t-PFD) as an accurate and effcient exponential series method, applicable to arbitrary bath correlation functions. The resulting numerical effciency of hierarchical equations of motion (HEOM) formalism is greatly optimized, especially in low temperature regimes that would be inacc...

Picturing the atomic migration pathways of catalysts in a reactive atmosphere is of central significance for uncovering the underlying catalytic mechanisms and directing the design of high-performance catalysts. Here, we describe a reduction-controlled atomic migration pathway that converts nanoparticles to single atom alloys (SAAs), which has rema...

We numerically calculate the local density of states in asymmetric Anderson model in mixed valence regime using hierarchical equations of motion approach. Based on the idea that the asymmetric line shape of local density of states around Fermi level stems from the interference between the single particle resonance and the Kondo resonance, we perfor...

In this work, we propose the Prony fitting decomposition (PFD) as an accurate and efficient exponential series method, applicable to arbitrary interacting bath correlation functions. The resulting hierarchical equations of motion (HEOM) formalism is greatly optimized, especially in extremely low temperature regimes that would be inaccessible with o...

The fluctuation theorem, where the central quantity is the work distribution, is an important characterization of nonequilibrium thermodynamics. In this work, based on the dissipaton–equation–of– motion theory, we develop an exact method to evaluate the work distributions in quantum impurity system–bath mixing processes, in the presence of non-Mark...

In magnetic molecular junctions, the interactions between the local spin state at the transition metal center and the conduction electrons from the electrodes or substrates can bring about many interesting strong correlation effects. Spin excitation and the Kondo effect are two representative phenomena, where the spin-unpaired d or f electrons play...

The Peltier effect is the reverse phenomenon of the Seebeck effect, and has been observed experimentally in nanoscale junctions. However, despite its promising applications in local cooling of nanoelectronic devices, the role of strong electron correlations on such a phenomenon is still unclear. Here, by analyzing the thermoelectric properties of q...

The Kondo transport associated with the magnetic field in parallel‐coupled double quantum dots (PDQDs) is theoretically investigated using the hierarchical‐equation‐of‐motion approach (HEOM). In this system, the interdot tunneling induces an effective antiferromagnetic interaction; thus, its ground state is an orbital singlet associated with approx...

Nanosystems play an important role in many applications. Due to their complexity, it is challenging to accurately characterize their structure and properties. An important means to reach such a goal is computational simulation, which is grounded on ab initio electronic structure calculations. Low scaling and accurate electronic-structure algorithms...

Single-atom catalysts (SACs) are being witnessed a rapid development due to their high activity and selectivity toward diverse reactions. However, it remains a grand challenge in the general synthesis of SACs, particularly featuring identical chemical microenvironment and on the same support. Herein, we have developed a universal synthetic protocol...

Constructing two-dimensional (2D) structures for transition-metal oxides (TMOs) can optimize their electronic structures and enable high specific surface areas, thereby offering routes to enhancing the performance of TMOs in energy storage and conversion. However, most 2D TMOs, e.g., Fe2O3, remain so far synthetically challenging due to their intri...

The hierarchical equation of motion method has become one of the most popular numerical methods for describing the dissipative dynamics of open quantum systems linearly coupled to environment. However, its applications to systems with strong electron correlation are largely restrained by the computational cost, which is mainly caused by the high tr...

For quantum systems coupled with Gaussian environment, we observe that the environmental dissipative effect can be represented by statistical quasi-particles. This observation is then exploited to establish universal relations for some important steady state correlation functions, which involve hybrid reservoir modes. All these relations are valida...

Boosting the efficiency of heterogeneous single-atom catalysts (SACs) by adjusting the microenvironment of the active atom has recently attracted enormous attention. However, attempts to tune the spin-spin interaction between the SAC and its microenvironment have remained rather scarce. Some interesting questions can be raised, among which a fundam...

Boosting the efficiency of heterogeneous single-atom catalysts (SACs) by adjusting the microenvironment of the active atom has recently attracted enormous attention. However, attempts to tune the spin-spin interaction between the SAC and its microenvironment have remained rather scarce. Some interesting questions can be raised, among which a fundam...

In the pioneering work by R. A. Marcus, the solvation effect on electron transfer (ET) processes was investigated, giving rise to the celebrated nonadiabatic ET rate formula. In this work, on the basis of the thermodynamic solvation potentials analysis, we reexamine Marcus’ formula with respect to the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. In...

The past decade has seen an increasing interest in designing sophisticated density functional approximations (DFAs) by integrating the power of machine learning (ML) techniques. However, application of the ML-based DFAs is often confined to simple model systems. In this work, we construct an ML correction to the widely used Perdew-Burke-Ernzerhof (...

The dinuclear iron complex [(H2O)-FeIII-(ppq)-O-(ppq)-FeIII-Cl]3+ (FeIII(ppq), ppq = 2-(pyrid-2'-yl)-8-(1″,10″-phenanthrolin-2″-yl)-quinoline) demonstrates a catalytic activity about one order of magnitude higher than the mononuclear iron complex [Cl-FeIII(dpa)-Cl]+ (FeIII(dpa), dpa = N,N-di(1,10-phenanthrolin-2-yl)-N-isopentylamine) for the oxygen...

Circular dichroism (CD) is broadly employed for distinguishing molecular chiralities. However, its practical application is often limited by the weak magnitude of chiral signal. We propose to use azimuthally and radially polarized vector beams to probe CD spectra. By taking advantage of the strong longitudinal components of the vector beams, the tr...

Fine-tuning the magnetic anisotropy energy (MAE) of a magnetic molecule with a high precision of sub-meV has been realized experimentally by manipulating the tip of a scanning tunneling microscope (STM). Understanding the mechanisms behind the observed evolution of spin excitation energy is essentially important for potential spintronic application...

p> Boosting the efficiency of heterogeneous single-atom catalysts (SACs) by adjusting the microenvironment of the active atom has recently attracted enormous attention. However, attempts to tune the spin-spin interaction between the SAC and its microenvironment have remained rather scarce. Some interesting questions can be raised, among which a fu...

Turing patterns have been widely seen in living systems. Nevertheless, the synthesis of chemical Turing‐type structures in inorganic nanomaterials remains a huge challenge. In their Research Article (DOI: 10.1002/anie.202017016), Min‐Rui Gao and co‐workers constructed stationary Ag2Se Turing patterns on CoSe2 nanobelts via diffusion‐driven instabil...

Turing‐Muster sind in lebenden Systemen weithin bekannt, dennoch bleibt die Synthese von chemischen Turing‐Strukturen in anorganischen Nanomaterialien eine große Herausforderung. In ihrem Forschungsartikel (DOI: 10.1002/ange.202017016) konstruierten Min‐Rui Gao und Mitarbeiter stationäre Ag2Se‐Turing‐Muster auf CoSe2‐Nanogürteln über diffusionsgetr...

Although the Turing structures, or stationary reaction‐diffusion patterns, have received increasing attention in biology and chemistry, making such unusual patterns on inorganic solids is fundamentally challenging. We report a simple cation exchange approach to produce Turing‐type Ag2Se on CoSe2 nanobelts relied on diffusion‐driven instability. The...

Measuring local temperatures of open systems out of equilibrium is emerging as a novel approach to study the local thermodynamic properties of nanosystems. An operational protocol has been proposed to determine the local temperature by coupling a probe to the system and then minimizing the perturbation to a certain local observable of the probed sy...

Understanding the electronic dynamics on surfaces of materials is fundamentally important for applications including nanoelectronics, inhomogeneous catalysis, and photovoltaics. Time-dependent density-functional theory (TDDFT) has been successfully applied to predict excited-state properties of isolated and periodic systems. However, it cannot addr...

A novel Turing‐type Ag2Se‐CoSe2 structure has been synthesized, which possesses rich Ag2Se‐CoSe2 interfaces, exhibiting a 221 mV overpotential at a current density of 10 mA cm⁻² in 0.1 M KOH electrolyte with a high anodic energy efficiency of 84.5 %. Abstract Although the Turing structures, or stationary reaction‐diffusion patterns, have received...

The electronic configuration plays a crucial role in the activity of catalyst toward OER according to Shao-Horn’s principle. Herein, we demonstrated a facile strategy to modulate the electrons of doubly degenerated (eg) orbital for Co ions in Co4Nx (0 < x < 1) nanosheets via simply altering the N content for the enhanced OER catalytic activity. The...

Visualizing and controlling electron dynamics over femtosecond timescale play a key role in the design of next-generation electronic devices. Using simulations, we demonstrate the electronic oscillation inside the naphthalene molecule can be tracked by means of the tuning of delay time between two identical femtosecond laser pulses. Both the freque...

Molecular quasiparticle and excitation energies determine essentially the spectral characteristics measured in various spectroscopic experiments. Accurate prediction of these energies has been rather challenging for ground-state density functional methods, because the commonly adopted density function approximations suffer from delocalization error...

In this work, we develop the free-energy spectrum theory for thermodynamics of open quantum impurity systems that can be either fermionic or bosonic or combined. We identify two types of thermodynamic free-energy spectral functions for open quantum systems and further consider the thermodynamic limit, which supports the Gaussian–Wick description of...

This work presents a unified dissipaton-equation-of-motion (DEOM) theory and its evaluations on the Helmholtz free energy change due to the isotherm mixing of two isolated subsystems. One is a local impurity, and the other is a nonlocal Gaussian bath. DEOM constitutes a fundamental theory for such open quantum mixtures. To complete the theory, we a...

In the pioneering work by R. A. Marcus, the solvation effect on electron transfer (ET) processes was investigated, giving rise to the celebrated nonadiabatic ET rate formula. In this work, we reexamine this formula with respect to the Rice-Ramsperger-Kassel-Marcus (RRKM) theory that is used to be considered for adiabatic gas phase reactions. We gen...