Many-Body Effects on the Zero-Point Renormalization of the Band Structure

Antonius, Gabriel; Poncé, Samuel; Boulanger, P; Côté, Michel; Gonze, Xavier

doi:10.1103/physrevlett.112.215501

Cited by 178 publications

(300 citation statements)

References 40 publications

Supporting

Mentioning

257

Contrasting

Order By: Relevance

“…Vibrational renormalisations to electronic band gaps have recently been shown to be as large as −0.5 eV for diamond [59][60][61] and diamondoids 62 . We have therefore investigated the effects of electron-phonon coupling on the gaps of carbon chains.…”

Section: E Vibrational Renormalisationmentioning

confidence: 99%

Quasiparticle and excitonic gaps of one-dimensional carbon chains

Mostaani

Monserrat

Drummond

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We report diffusion quantum Monte Carlo (DMC) calculations of the quasiparticle and excitonic gaps of hydrogen-terminated oligoynes and polyyne. The electronic gaps are found to be very sensitive to the atomic structure in these systems. We have therefore optimised the geometry of polyyne by directly minimising the DMC energy with respect to the lattice constant and the Peierlsinduced carbon-carbon bond-length alternation. We find the bond-length alternation of polyyne to be 0.136(2)Å and the excitonic and quasiparticle gaps to be 3.30(7) and 3.4(1) eV, respectively. The DMC zone-centre longitudinal optical phonon frequency of polyyne is 2084(5) cm −1 , which is consistent with Raman spectroscopic measurements for large oligoynes.

show abstract

Section: E Vibrational Renormalisationmentioning

confidence: 99%

Quasiparticle and excitonic gaps of one-dimensional carbon chains

Mostaani

Monserrat

Drummond

et al. 2016

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…The inclusion of nuclear quantum effects (NQEs) noticeably modifies the structural and dynamical properties of liquid water [23][24][25][26][27][28][29]. In the context of the electronic structure, the quantum zero-point motion of nuclei renormalizes the electronic band gap [30][31][32][33][34][35][36][37][38][39]. As a consequence, quantum effects play an integral part in the description of the electronic structure of liquid water, but very often their importance is underappreciated in ab initio MD simulations.…”

mentioning

confidence: 99%

Ab initio Electronic Structure of Liquid Water

et al. 2016

View full text Add to dashboard Cite

Self-consistent GW calculations with efficient vertex corrections are employed to determine the electronic structure of liquid water. Nuclear quantum effects are taken into account through ab initio pathintegral molecular dynamics simulations. We reveal a sizable band-gap renormalization of up to 0.7 eV due to hydrogen-bond quantum fluctuations. Our calculations lead to a band gap of 8.9 eV, in accord with the experimental estimate. We further resolve the ambiguities in the band-edge positions of liquid water. The valence-band maximum and the conduction-band minimum are found at −9.4 and −0.5 eV with respect to the vacuum level, respectively. DOI: 10.1103/PhysRevLett.117.186401 Liquid water is such a ubiquitous substance that it has been the subject of upsurging research efforts for the past 30 years. Of particular importance is the electronic structure of liquid water, the significance of which has been recently highlighted in clean-energy technologies through semiconductor-assisted artificial photosynthesis [1,2]. A good understanding of the electronic structure of water is a prerequisite toward the design of photocatalytic systems with high catalytic activity.The extended hydrogen-bond network of liquid water gives rise to the formation of electronic bands. The valence band maximum (VBM) is characterized by the localized 2p z electrons of O atoms. The conduction band minimum (CBM) derives from the antibonding orbitals of O-H bonds, and is at variance much more extended. Experimentally determined positions of these band edge states have yet to reach a consensus. Early ultraviolet (UV) photoemission experiments by Delahay and collaborators reported photoemission threshold energies of 9.3 [3] and 10.06 eV [4]. More recent work by Winter et al. employed the liquid microjet technique and found a threshold energy of 9.9 eV [5]. For the unoccupied states, inverse photoemission and photoionization measurements placed the CBM at −1.2 eV with respect to the vacuum level [6,7]. This value was later revised to −0.74 eV, in light of the observation that excess electrons in liquid water could be initially captured in a localized trap state below the actual CBM [8]. Altogether, these measurements allude to a band gap of 8.7 eV, but associated with a sizable uncertainty of AE0.6 eV.To shed light on the electronic structure of water, it is necessary to resort to a fully ab initio method, which avoids the use of experimental input. Ab initio molecular dynamics (MD) simulations based on Kohn-Sham density-functional theory (DFT) have been extensively carried out to understand the structural and dynamical properties of water and of aqueous solutions. It is well recognized that the use of semilocal density functionals precludes a faithful description of the electronic structure and the predicted band gap of liquid water is apparently too small [9,10]. Hybrid functionals improve the description of the electronic structure [10], but the mixing parameter of the Fock exchange is not known a priori without the input from experiment ...

show abstract

“…In semiconductors, the highly heterogeneous electron-phonon interactions (e.g. in polar semiconductors with Fröhlich interactions [9]) and, in some cases, the higher lattice thermal conductivity in comparison to metals weaken the hypothesis of a thermalized phononic subsystem [10,11], hence calling for the reexamination of the 2T physical picture in semiconductors.In this context, the advent of first-principles techniques able to predict the mode-and energy-resolved electronphonon [12][13][14] and phonon-phonon interactions [15,16] provides an important opportunity: In their modern implementations [13,16,17], these methods have been able to predict lattice thermal conductivities [18][19][20][21], the temperature-and pressure-dependence of the electronic bandgap [22][23][24][25][26][27][28], electrical conductivities [29,30], and hot carrier dynamics [31,32]. However, to the best of our knowledge and despite these early successes, these approaches have yet to be applied to the computation of electron-induced, non-equilibrium phonon distributions and their effects on thermal relaxation of electrons.…”

mentioning

confidence: 99%

Theory of Thermal Relaxation of Electrons in Semiconductors

Sridhar¹,

Chan²,

Darancet³

2017

Phys. Rev. Lett.

View full text Add to dashboard Cite

We compute the transient dynamics of phonons in contact with high energy "hot" charge carriers in 12 polar and non-polar semiconductors, using a first-principles Boltzmann transport framework. For most materials, we find that the decay in electronic temperature departs significantly from a single-exponential model at times ranging from 1 ps to 15 ps after electronic excitation, a phenomenon concomitant with the appearance of non-thermal vibrational modes. We demonstrate that these effects result from the slow thermalization within the phonon subsystem, caused by the large heterogeneity in the timescales of electron-phonon and phonon-phonon interactions in these materials. We propose a generalized 2-temperature model accounting for the phonon thermalization as a limiting step of electron-phonon thermalization, which captures the full thermal relaxation of hot electrons and holes in semiconductors. A direct consequence of our findings is that, for semiconductors, information about the spectral distribution of electron-phonon and phonon-phonon coupling can be extracted from the multi-exponential behavior of the electronic temperature.Following the seminal works of Kaganov et al. [1] and Allen [2], the thermalization of a system of highly energetic charge carriers with a lattice is frequently understood as an electron-phonon mediated, temperature equilibration process with a single characteristic timescale τ el-ph . Such description, referred to as the two temperature (2T) model, relies on the central assumption that both electrons and phonons remain in distinct thermal equilibria and can therefore be described by timedependent temperatures T el (t) and T ph (t) during the thermal equilibration process. In metals, due to the relative homogeneity of the electron-phonon interactions and the rates of thermalization within the electronic and phononic subsystems, the hypothesis of subsystem-wide thermal equilibrium is generally accurate, and the 2T model has been successful in modeling ultra-fast laser heating [3][4][5], despite some notable deviations from the 2T predictions in graphene and aluminum [6][7][8]. In semiconductors, the highly heterogeneous electron-phonon interactions (e.g. in polar semiconductors with Fröhlich interactions [9]) and, in some cases, the higher lattice thermal conductivity in comparison to metals weaken the hypothesis of a thermalized phononic subsystem [10,11], hence calling for the reexamination of the 2T physical picture in semiconductors.In this context, the advent of first-principles techniques able to predict the mode-and energy-resolved electronphonon [12][13][14] and phonon-phonon interactions [15,16] provides an important opportunity: In their modern implementations [13,16,17], these methods have been able to predict lattice thermal conductivities [18][19][20][21], the temperature-and pressure-dependence of the electronic bandgap [22][23][24][25][26][27][28], electrical conductivities [29,30], and hot carrier dynamics [31,32]. However, to the best of our knowledge and despite these ...

show abstract

Many-Body Effects on the Zero-Point Renormalization of the Band Structure

Cited by 178 publications

References 40 publications

Quasiparticle and excitonic gaps of one-dimensional carbon chains

Quasiparticle and excitonic gaps of one-dimensional carbon chains

Ab initio Electronic Structure of Liquid Water

Theory of Thermal Relaxation of Electrons in Semiconductors

Contact Info

Product

Resources

About