@article{wilmington_ardekani_rustagi_bataller_kemper_younts_gundogdu_2021, title={Fermi liquid theory sheds light on hot electron-hole liquid in 1L-MoS2}, volume={103}, ISSN={["2469-9969"]}, url={https://doi.org/10.1103/PhysRevB.103.075416}, DOI={10.1103/PhysRevB.103.075416}, abstractNote={Room-temperature electron-hole liquid has recently been experimentally identified in low-dimensional transition metal dichalcogenides. Here, the authors demonstrate that a first-principles Fermi liquid model effectively predicts the photoluminescence response of this phenomenon. Using density functional theory, in conjunction with previous Raman and photoluminescence spectroscopy results, they present a consistent quantitative picture of the electron-hole liquid phase transition in suspended, heat-strained 1$L$-MoS${}_{2}$ monolayers. They show a 23-fold increase in photoluminescence per unit of direct gap carrier density and 9:1 indirect-direct hole population ratio at high strain.}, number={7}, journal={PHYSICAL REVIEW B}, author={Wilmington, R. L. and Ardekani, H. and Rustagi, A. and Bataller, A. and Kemper, A. F. and Younts, R. A. and Gundogdu, K.}, year={2021}, month={Feb} }
 @article{lippy_bland_bataller_2021, title={Fundamental interactions in a classical Wigner system}, volume={104}, ISSN={["2470-0053"]}, DOI={10.1103/PhysRevE.104.L023202}, abstractNote={Wigner crystallization in macroscopic systems provides a simple avenue for studying classical many-body physics. The Coulomb repulsion of millimeter-sized conducting spheres rolling on a high potential surface enables the self-assembly of ordered structures. Prior attempts at formulating pairwise force models for Wigner islands have resulted in different functional forms with no apparent consensus. In this study, we explore fundamental particle interactions using the finite element method to solve the electrostatic problem for one-, two-, and many-sphere configurations. Analysis of charge and force shows three interaction regimes parametrized by the packing fraction, which includes many-body force behavior for compact geometries. We find that the force relationship between spheres is accurately represented by an aligned dipole model over all configurations. Both the finite element method and aligned dipole models were validated in absolute terms using an experimental setup featuring a gravity potential. Future dynamic studies, which rely on accurate force relationships, can now be treated.}, number={2}, journal={PHYSICAL REVIEW E}, author={Lippy, Matthew and Bland, Hayden and Bataller, Alexander}, year={2021}, month={Aug} }
 @article{nevola_bataller_kumar_sridhar_frick_o'donnell_ade_maggard_kemper_gundogdu_et al._2021, title={Timescales of excited state relaxation in alpha-RuCl3 observed by time-resolved two-photon photoemission spectroscopy}, volume={103}, ISSN={["2469-9969"]}, url={https://doi.org/10.1103/PhysRevB.103.245105}, DOI={10.1103/PhysRevB.103.245105}, abstractNote={The nonequilibrium properties of strongly correlated materials present a target in the search for new phases of matter. It is important to observe the types of excitations that exist in these materials and their associated relaxation dynamics. We have studied the photoexcitations in a spin-orbit assisted Mott insulator $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Ru}{\mathrm{Cl}}_{3}$ using time-resolved two-photon photoemission spectroscopy and transient reflection spectroscopy. We find that photoexcited carriers (doublons) in the upper Hubbard band rapidly relax to Mott-Hubbard excitons on a timescale of less than 200 fs. Subsequently, further relaxation of these lower-energy quasiparticles occurs with an energy-dependent time constant of that ranges from 370 to 600 fs due to exciton cooling. The population of Mott-Hubbard excitons persists for timescales up to several microseconds.}, number={24}, journal={PHYSICAL REVIEW B}, author={Nevola, Dan and Bataller, Alexander and Kumar, Ankit and Sridhar, Samanvitha and Frick, Jordan and O'Donnell, Shaun and Ade, Harald and Maggard, Paul A. and Kemper, Alexander F. and Gundogdu, Kenan and et al.}, year={2021}, month={Jun} }
 @article{bataller_younts_rustagi_yu_ardekani_kemper_cao_gundogdu_2019, title={Dense Electron-Hole Plasma Formation and Ultra-Long Charge Lifetime in Monolayer MoS2 via Material Tuning}, journal={Nano letters}, publisher={American Chemical Society}, author={Bataller, Alexander W and Younts, Robert and Rustagi, Avinash and Yu, Yiling and Ardekani, Hossein and Kemper, Alexander and Cao, Linyou and Gundogdu, Kenan}, year={2019} }
 @article{bataller_latshaw_koulakis_putterman_2019, title={Dynamics of strongly coupled two-component plasma via ultrafast spectroscopy}, url={https://doi.org/10.1364/OL.44.005832}, DOI={10.1364/OL.44.005832}, abstractNote={A combination of ultrafast emission and transmission spectroscopy is presented that provides a model-independent temperature measurement and tracking of the expansion dynamics for a dense, strongly coupled plasma. For femtosecond laser breakdown of hydrogen gas at 10 bar, we observe a 30,000 K two-component plasma for hundreds of picoseconds where both electrons and protons have a strong coupling parameter value of $\Gamma \sim{0.5}$Γ∼0.5. Furthermore, the plasma's degree of ionization (45%) results in a condition where the Debye screening length (6 Å) is less than the interatomic spacing (13 Å). Plasma formation occurs under an isochoric initial condition, which simplifies hydrodynamic modeling of the plasma channel expansion. The channel radius is found to accelerate at a constant rate until the front is moving with the speed of sound. Comparing hydrogen and deuterium for the same breakdown conditions grants unique insight into the hydrodynamics of strongly coupled plasma due to their nearly identical electronic structure yet large mass difference. The ultimate goal of these experiments is to access a plasma regime where continuum mechanics become nonlocal, as compared with the hydrodynamic motion described by the Navier-Stokes equations.}, journal={Optics Letters}, author={Bataller, Alexander and Latshaw, Alexandra and Koulakis, John P. and Putterman, Seth}, year={2019}, month={Dec} }
 @article{nevola_hoffman_bataller_ade_gundogdu_dougherty_2019, title={Rigid valence band shift due to molecular surface counter-doping of MoS2}, volume={679}, ISSN={["1879-2758"]}, DOI={10.1016/j.susc.2018.09.016}, abstractNote={Adsorption of the acceptor material tetracyanoquinodimethane can control optoelectronic properties of MoS2 by accepting defect generated excess negative charge from the surface that would otherwise interfere with radiative decay processes. Angle Resolved Photoelectron Spectroscopy measurements show that the MoS2 band structure near the Γ point shifts rigidly upward by ∼0.2 eV for a complete surface coverage of acceptor species as expected for an upward Fermi level shift due to charge transfer to the TCNQ. The molecular adsorbate orbitals visible in photoemission are indicative of an anionic species, consistent with interfacial charge transfer but without evidence for hybrid states arising from covalent adsorbate-surface interactions. Thus, our interface studies support the notion that molecular adsorbates are a useful tool for controlling optoelectronic functionality in 2D materials without fundamentally modifying their favorable band structures.}, journal={SURFACE SCIENCE}, publisher={North-Holland}, author={Nevola, D. and Hoffman, B. C. and Bataller, A. and Ade, H. and Gundogdu, K. and Dougherty, D. B.}, year={2019}, month={Jan}, pages={254–258} }
 @article{yu_bataller_younts_yu_li_puretzky_geohegan_gundogdu_cao_2019, title={Room-Temperature Electron-Hole Liquid in Monolayer MoS2}, volume={13}, ISSN={["1936-086X"]}, DOI={10.1021/acsnano.9b04124}, abstractNote={Excitons in semiconductors are usually non-interacting and behave like an ideal gas, but may condense to a strongly-correlated liquid-like state, i.e. electron-hole liquid (EHL), at high density and appropriate temperature. EHL is a macroscopic quantum state with exotic properties and represents the ultimate attainable charge excitation density in steady states. It bears great promise for a variety of fields such as ultrahigh-power photonics and quantum science and technology. However, the condensation of gas-like excitons to EHL has often been restricted to cryogenic temperatures, which significantly limits the prospect of EHL for use in practical applications. Herein we demonstrate the formation of EHL at room temperature in monolayer MoS2 by taking advantage of the monolayer's extraordinarily strong exciton binding energy. This work demonstrates the potential for the liquid-like state of charge excitations to be a useful platform for the studies of macroscopic quantum phenomena and the development of optoelectronic devices.}, number={9}, journal={ACS NANO}, author={Yu, Yiling and Bataller, Alexander W. and Younts, Robert and Yu, Yifei and Li, Guoqing and Puretzky, Alexander A. and Geohegan, David B. and Gundogdu, Kenan and Cao, Linyou}, year={2019}, month={Sep}, pages={10351–10358} }
 @article{younts_bataller_ardekani_gundogdu_2018, title={Catastrophic Ionization in Monolayer Transition Metal Dichalcogenides}, journal={Bulletin of the American Physical Society}, publisher={American Physical Society}, author={Younts, Robert and Bataller, Alexander and Ardekani, Hossein and Gundogdu, Kenan}, year={2018} }
 @article{bataller_younts_gundogdu_2018, title={Electron-Hole Liquid Formation in Monolayer Semiconductors at Room Temperature}, journal={Bulletin of the American Physical Society}, publisher={American Physical Society}, author={Bataller, Alexander and Younts, Robert and Gundogdu, Kenan}, year={2018} }
 @article{nevola_abdurazakov_boltersdorf_bataller_gundogdu_maggard_kemper_dougherty_2018, title={Phonon-Mediated Excited State Decay in High Energy Unoccupied Bands of the Topological Insulator Bi 1.5 Sb 0.5 Te 1.7 Se 1.3}, journal={Bulletin of the American Physical Society}, publisher={American Physical Society}, author={Nevola, Daniel and Abdurazakov, Omadillo and Boltersdorf, Jonathan and Bataller, Alexander and Gundogdu, Kenan and Maggard, Paul and Kemper, Alexander and Dougherty, Daniel}, year={2018} }
 @article{yu_bataller_younts_yu_li_puretzky_geohegan_gundogdu_cao_2017, title={Room-Temperature Electron-Hole Liquid in Monolayer MoS2}, journal={arXiv preprint arXiv:1710.09538}, author={Yu, Yiling and Bataller, Alexander and Younts, Robert and Yu, Yifei and Li, Guoqing and Puretzky, Alexander A and Geohegan, David B and Gundogdu, Kenan and Cao, Linyou}, year={2017} }
 @article{koulakis_bataller_pree_putterman_2016, title={Comment on "Fluid modeling of a high-voltage nanosecond pulsed xenon microdischarge" [Phys. Plasmas 23, 073513 (2016)]}, volume={23}, ISSN={["1089-7674"]}, DOI={10.1063/1.4967851}, abstractNote={Simulations of sparks in 10 atmosphere Xenon gas by Levko and Raja [Phys. Plasmas 23, 073513 (2016)] are unable to reproduce the experimental fact of their opacity to visible light [Bataller et al., Appl. Phys. Lett. 105, 223501 (2014)]. Levko and Raja have argued the discrepancy is due to enhanced ionization from the probing laser radiation and/or cathode field emission. Having observed comparable opacity in similar systems without probing lasers and without electrodes, we instead argue that the enhanced ionization is a thermodynamic result of dense plasma screening effects that lower the effective ionization potential. Levko and Raja do not adequately address these density effects in their spark discharge simulations.}, number={11}, journal={PHYSICS OF PLASMAS}, author={Koulakis, J. and Bataller, A. and Pree, S. and Putterman, S.}, year={2016}, month={Nov} }
 @article{bataller_koulakis_pree_putterman_2016, title={Comment on “Early stage time evolution of a dense nanosecond microdischarge used in fast optical switching applications”[Phys. Plasmas 22, 123518 (2015)]}, volume={23}, number={3}, journal={Physics of Plasmas}, publisher={AIP Publishing}, author={Bataller, A and Koulakis, J and Pree, S and Putterman, S}, year={2016}, pages={034705} }
 @article{zheng_awartani_gautam_liu_qin_li_bataller_gundogdu_ade_hou_et al._2016, title={Efficient Charge Transfer and Fine-Tuned Energy Level Alignment in a THF-Processed Fullerene-Free Organic Solar Cell with 11.3% Efficiency}, volume={29}, ISSN={0935-9648}, url={http://dx.doi.org/10.1002/adma.201604241}, DOI={10.1002/adma.201604241}, abstractNote={Fullerene-free organic solar cells show over 11% power conversion efficiency, processed by low toxic solvents. The applied donor and acceptor in the bulk heterojunction exhibit almost the same highest occupied molecular orbital level, yet exhibit very efficient charge creation.}, number={5}, journal={Advanced Materials}, publisher={Wiley}, author={Zheng, Z. and Awartani, O. M. and Gautam, B. and Liu, D. L. and Qin, Y. P. and Li, W. N. and Bataller, Alexander and gundogdu and Ade, H. and Hou, J. H. and et al.}, year={2016}, month={Nov}, pages={1604241} }
 @book{putterman_bataller_koulakis_pree_latshaw_2016, title={Energy Flow in Dense Off-Equilibrium Plasma}, institution={University of California, Los Angeles Los Angeles United States}, author={Putterman, Seth and Bataller, Alex and Koulakis, John and Pree, Seth and Latshaw, Alexandra}, year={2016} }
 @article{bataller_putterman_pree_koulakis_2016, title={Observation of Shell Structure, Electronic Screening, and Energetic Limiting in Sparks}, volume={117}, ISSN={0031-9007 1079-7114}, url={http://dx.doi.org/10.1103/PhysRevLett.117.085001}, DOI={10.1103/PhysRevLett.117.085001}, abstractNote={We study the formation of micron-sized spark discharges in high-pressure xenon on the nanosecond time scale. The spark's energy per length is measured through the expansion dynamics of the generated shock wave, and is observed to scale linearly with the spark radius. At the same time, the surface temperature of the spark channel remains constant. Together, these observations allow us to conclude that the spark channel, up to 40  μm in overall radius, is actually an energetically hollow shell about 20  μm thick. Further, the energy per nucleus in the shell is about 15 eV, independent of size and density. To reconcile these findings with the opacity to visible light, we appeal to collective screening processes that dramatically lower the effective ionization potential, allowing a much higher electron density than is otherwise expected. Thus, nanosecond measurements of sparks provide access to the thermodynamics and kinetics of strongly correlated plasmas.}, number={8}, journal={Physical Review Letters}, publisher={American Physical Society (APS)}, author={Bataller, A. and Putterman, S. and Pree, S. and Koulakis, J.}, year={2016}, month={Aug}, pages={085001} }
 @book{bataller_thornton_latshaw_pree_koulakis_putterman_2015, title={Noble Gas Plasmas with Metallic Conductivity: A New Light Source from a New State of Matter}, institution={University of California-Los Angeles Los Angeles United States}, author={Bataller, Alex and Thornton, Alex and Latshaw, Alex and Pree, Seth and Koulakis, John and Putterman, Seth}, year={2015} }
 @inproceedings{bataller_plateau_kappus_putterman_2014, title={A new class of strongly coupled plasmas inspired by sonoluminescence}, booktitle={APS Meeting Abstracts}, author={Bataller, Alexander and Plateau, Guillaume and Kappus, Brian and Putterman, Seth}, year={2014} }
 @article{bataller_plateau_kappus_putterman_2014, title={Blackbody Emission from Laser Breakdown in High-Pressure Gases}, volume={113}, ISSN={0031-9007 1079-7114}, url={http://dx.doi.org/10.1103/PhysRevLett.113.075001}, DOI={10.1103/PhysRevLett.113.075001}, abstractNote={Laser induced breakdown of pressurized gases is used to generate plasmas under conditions where the atomic density and temperature are similar to those found in sonoluminescing bubbles. Calibrated streak spectroscopy reveals that a blackbody persists well after the exciting femtosecond laser pulse has turned off. Deviation from Saha's equation of state and an accompanying large reduction in ionization potential are observed at unexpectedly low atomic densities-in parallel with sonoluminescence. In laser breakdown, energy input proceeds via excitation of electrons whereas in sonoluminescence it is initiated via the atoms. The similar responses indicate that these systems are revealing the thermodynamics and transport of a strongly coupled plasma.}, number={7}, journal={Physical Review Letters}, publisher={American Physical Society (APS)}, author={Bataller, A. and Plateau, G. R. and Kappus, B. and Putterman, S.}, year={2014}, month={Aug}, pages={075001} }
 @article{bataller_kappus_camara_putterman_2014, title={Collision Time Measurements in a Sonoluminescing Microplasma with a Large Plasma Parameter}, volume={113}, ISSN={0031-9007 1079-7114}, url={http://dx.doi.org/10.1103/PhysRevLett.113.024301}, DOI={10.1103/PhysRevLett.113.024301}, abstractNote={The plasma which forms inside of a micron-sized sonoluminescing bubble in water for under a nanosecond has been probed with 3 ns long laser pulses. A comparison of the response to 532 and 1064 nm light indicates that the plasma number density is about 2×10(21)  cm(-3) and that transport properties are dominated by strong screening and correlation effects. The spherical shape, well-defined atomic density, and blackbody temperature make the sonoluminescing plasma a test bed for theories of strongly coupled plasmas. The plasma in this experiment distinguishes between competing theories of strong, intermediate, and weak effective screening.}, number={2}, journal={Physical Review Letters}, publisher={American Physical Society (APS)}, author={Bataller, A. and Kappus, B. and Camara, C. and Putterman, S.}, year={2014}, month={Jul}, pages={024301} }
 @book{bataller_2014, title={Exploring the Universality of Sonoluminescence}, publisher={University of California, Los Angeles}, author={Bataller, Alexander William}, year={2014} }
 @article{bataller_koulakis_pree_putterman_2014, title={Nanosecond high-power dense microplasma switch for visible light}, volume={105}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4902914}, DOI={10.1063/1.4902914}, abstractNote={Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.}, number={22}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Bataller, A. and Koulakis, J. and Pree, S. and Putterman, S.}, year={2014}, month={Dec}, pages={223501} }
 @article{kappus_bataller_putterman_2013, title={Energy Balance for a Sonoluminescence Bubble Yields a Measure of Ionization Potential Lowering}, volume={111}, ISSN={0031-9007 1079-7114}, url={http://dx.doi.org/10.1103/PhysRevLett.111.234301}, DOI={10.1103/PhysRevLett.111.234301}, abstractNote={Application of energy conservation between input sound and the microplasma which forms at the moment of sonoluminescence places bounds on the process, whereby the gas is ionized. Detailed pulsed Mie scattering measurements of the radius versus time for a xenon bubble in sulfuric acid provide a complete characterization of the hydrodynamics and minimum radius. For a range of emission intensities, the blackbody spectrum emitted during collapse matches the minimum bubble radius, implying opaque conditions are attained. This requires a degree of ionization >36%. Analysis reveals only 2.1±0.6  eV/atom of energy available during light emission. In order to unbind enough charge, collective processes must therefore reduce the ionization potential by at least 75%. We interpret this as evidence that a phase transition to a highly ionized plasma is occurring during sonoluminescence.}, number={23}, journal={Physical Review Letters}, publisher={American Physical Society (APS)}, author={Kappus, B. and Bataller, A. and Putterman, S. J.}, year={2013}, month={Dec}, pages={234301} }