Jakub Schusser - Academia.edu (original) (raw)

Papers by Jakub Schusser

Research paper thumbnail of Objemové a povrchové elektronické stavy v dopovaném polokovu HfTe2

Článek se zabývá popisem elektronové struktury dopovaného polokovu HfTe2 doplněnou o teoretické v... more Článek se zabývá popisem elektronové struktury dopovaného polokovu HfTe2 doplněnou o teoretické výpočty.The dosing of layered materials with alkali metals has become a commonly used strategy in ARPES experiments. However, precisely what occurs under such conditions, both structurally and electronically, has remained a matter of debate. Here we perform a systematic study of 1T-HfTe2, a prototypical semimetal of the transition metal dichalcogenide family. By utilizing photon energy-dependent angle-resolved photoemission spectroscopy (ARPES), we have investigated the electronic structure of this material as a function of potassium (K) deposition. From the kz maps, we observe the appearance of 2D dispersive bands after electron dosing, with an increasing sharpness of the bands, consistent with the wave-function confinement at the topmost layer. In our highest-dosing cases, a monolayerlike electronic structure emerges, presumably as a result of intercalation of the alkali metal. Here, by...

Research paper thumbnail of Processing of two-step γ cascade data from 151Eu(n,γ)152Eu reaction

1 Fotonové silové funkce, které v rámci statistického přístupu popisují rozdělení pravděpodobnost... more 1 Fotonové silové funkce, které v rámci statistického přístupu popisují rozdělení pravděpodobnosti vyzáření fotonu daným jádrem při deexcitaci ze vzbuzeného stavu, lze zkoumat například pomocí dvoukrokových gamma kaskád. Metoda dvoukrokových gamma kaskád byla poprvé představena v padesátých letech minulého století. Předmětem našeho zkoumání je studium dvoukrokových gamma kaskád následujících záchyt tepelného neutronu v reakci 151 Eu(n,γ)152 Eu. Experimentální data byla měřena na výzkumném reaktoru v Řeži u Prahy. Získaná emisní spektra z tepelného záchytu neutronu nejprve energeticky okalibrujeme, poté provedeme účinnostní kalibraci a po dalším zpracování porovnáme naměřená data s výsledky teoretických simulací.1 Photon strength functions in terms of statistical approach to a nuclear decay describe the probability distribution of photon emission by given nucleus. They can be studied using two step gamma cascades. The two step gamma cascade method was firstly introduced in fifties of...

Research paper thumbnail of Surface band characters of the Weyl semimetal candidate material MoTe2 revealed by one-step angle-resolved photoemission theory

Research paper thumbnail of Single-crystal studies and electronic structure investigation of the room-temperature semiconductor NaMnAs

Physical Review B, 2022

We report synthesis of single crystalline NaMnAs, confirm its antiferromagnetic order and charact... more We report synthesis of single crystalline NaMnAs, confirm its antiferromagnetic order and characterise the sample by photoemission spectroscopy. The electronic structure was studied using optical transmittance, x-ray and ultraviolet spectroscopy and by theoretical modeling using local density approximation (LDA) extended to LDA+U when Heisenberg model parameters were determined. Optical transmittance measurement have confirmed the theoretical predictions that NaMnAs is a semiconductor. Also the Néel temperature was closer determined for the first time from temperature dependence of magnetization, in agreement with our Monte Carlo simulations.

Research paper thumbnail of Multidimensional XUV Photoemission Spectroscopy of 1T-TiTe2 for different crystal orientations

We performed extreme ultraviolet (21.7 eV) multidimensional angle-resolved photoemission spectros... more We performed extreme ultraviolet (21.7 eV) multidimensional angle-resolved photoemission spectroscopy for two different crystal orientations linked to each other by mirror symmetry, we isolate and identify the role of orbital texture in photoemission from the transition metal dichalcogenide 1T-TiTe$_2$. By comparing these experimental results with theoretical calculations based on both a quantitative one-step model of photoemission and an intuitive tight-binding model, we unambiguously demonstrate the link between the momentum-dependent orbital orientation and the emergence of strong intrinsic linear dichroism in the photoelectron angular distributions.

Research paper thumbnail of Signature of Hidden Orbital-Texture in Photoemission Time-Reversal Dichroism

arXiv: Materials Science, 2020

We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe$_2$ for different c... more We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe$_2$ for different crystal orientations linked to each other by time-reversal symmetry. We introduce a new observable called time-reversal dichroism, which quantifies the modulation of the photoemission intensity upon effective time-reversal operation. We demonstrate that the hidden orbital-texture of the crystal's electronic structure leaves its imprint onto the time-reversal dichroism, due to multiple orbitals interference effects in photoemission. Our experimental results are in quantitative agreement with state-of-the-art fully relativistic calculations performed using the one-step model of photoemission. While spin-resolved ARPES probes the spin component of entangled spin-orbital texture in multiorbital systems, we demonstrate that time-reversal dichroism is sensitive to its orbital-texture counterpart.

Research paper thumbnail of Unveiling the orbital texture of 1T-TiTe2 using intrinsic linear dichroism in multidimensional photoemission spectroscopy

npj Quantum Materials, 2021

The momentum-dependent orbital character in crystalline solids, referred to as orbital texture, i... more The momentum-dependent orbital character in crystalline solids, referred to as orbital texture, is of capital importance in the emergence of symmetry-broken collective phases, such as charge density waves as well as superconducting and topological states of matter. By performing extreme ultraviolet multidimensional angle-resolved photoemission spectroscopy for two different crystal orientations linked to each other by mirror symmetry, we isolate and identify the role of orbital texture in photoemission from the transition metal dichalcogenide 1T-TiTe2. By comparing our experimental results with theoretical calculations based on both a quantitative one-step model of photoemission and an intuitive tight-binding model, we unambiguously demonstrate the link between the momentum-dependent orbital orientation and the emergence of strong intrinsic linear dichroism in the photoelectron angular distributions. Our results represent an important step towards going beyond band structure (eigenv...

Research paper thumbnail of Revealing Hidden Orbital Pseudospin Texture with Time-Reversal Dichroism in Photoelectron Angular Distributions

Physical Review Letters, 2020

Research paper thumbnail of Bulk and surface electronic states in the dosed semimetallic HfTe2

Research paper thumbnail of Bixbyite-Ta2N2O film prepared by HiPIMS and postdeposition annealing: Structure and properties

Journal of Vacuum Science & Technology A, 2020

Nb-doped TiO 2 coatings developed by high power impulse magnetron sputtering-chemical vapor depos... more Nb-doped TiO 2 coatings developed by high power impulse magnetron sputtering-chemical vapor deposition hybrid deposition process

Research paper thumbnail of Spin, time, and angle resolved photoemission spectroscopy on WTe2

Physical Review Research, 2020

Research paper thumbnail of Angle-resolved photoemission calculations of WTe2 compared to experiment

APPLIED PHYSICS OF CONDENSED MATTER (APCOM 2019), 2019

Molybdenum dichalcogenides are probably the most studied single layer TMDCs by virtue of being ap... more Molybdenum dichalcogenides are probably the most studied single layer TMDCs by virtue of being appealing for sundry possible applications suchlike transistors, diodes, solar cells or more fundamental studies of spin or valley pseudospin and their interactions. Tungsten-based counterparts are on the other hand evincing much stronger spin-orbit coupling due to which all the spin-related effects are more stable at room temperature and thus more feasible for application. WTe 2 , a type-II Weyl semimetal is in particular interesting due to having two pairs of spin-differentiated Weyl points above Fermi energy. We have conducted several experiments following the evolution of the band dispersion in the vicinity of X and Y points of the Brillouin zone of WTe 2 which is substantial for understanding the fundamental properties of the structure-property relation of the system. Ab-initio set of photoemission calculations was performed using SPR-KKR package and compared to experimental results.

Research paper thumbnail of Ramseyova teorie aneb příklady, které jsou pro počítač příliš složité

summary:Ramsey theory deals with problems asking for the minimum number of elements which guarant... more summary:Ramsey theory deals with problems asking for the minimum number of elements which guarantees a particular property. These include e.g. Party Problem, Happy End Problem or Van der Waerden Problem. Solving the problems of this kind is rather time-consuming for a computer, but the result can often be obtained by mathematical reasoning with pencil and paper. Ramsey theory was deeply developed by a famous Hungarian mathematician Pál Erdös

Research paper thumbnail of Objemové a povrchové elektronické stavy v dopovaném polokovu HfTe2

Článek se zabývá popisem elektronové struktury dopovaného polokovu HfTe2 doplněnou o teoretické v... more Článek se zabývá popisem elektronové struktury dopovaného polokovu HfTe2 doplněnou o teoretické výpočty.The dosing of layered materials with alkali metals has become a commonly used strategy in ARPES experiments. However, precisely what occurs under such conditions, both structurally and electronically, has remained a matter of debate. Here we perform a systematic study of 1T-HfTe2, a prototypical semimetal of the transition metal dichalcogenide family. By utilizing photon energy-dependent angle-resolved photoemission spectroscopy (ARPES), we have investigated the electronic structure of this material as a function of potassium (K) deposition. From the kz maps, we observe the appearance of 2D dispersive bands after electron dosing, with an increasing sharpness of the bands, consistent with the wave-function confinement at the topmost layer. In our highest-dosing cases, a monolayerlike electronic structure emerges, presumably as a result of intercalation of the alkali metal. Here, by...

Research paper thumbnail of Processing of two-step γ cascade data from 151Eu(n,γ)152Eu reaction

1 Fotonové silové funkce, které v rámci statistického přístupu popisují rozdělení pravděpodobnost... more 1 Fotonové silové funkce, které v rámci statistického přístupu popisují rozdělení pravděpodobnosti vyzáření fotonu daným jádrem při deexcitaci ze vzbuzeného stavu, lze zkoumat například pomocí dvoukrokových gamma kaskád. Metoda dvoukrokových gamma kaskád byla poprvé představena v padesátých letech minulého století. Předmětem našeho zkoumání je studium dvoukrokových gamma kaskád následujících záchyt tepelného neutronu v reakci 151 Eu(n,γ)152 Eu. Experimentální data byla měřena na výzkumném reaktoru v Řeži u Prahy. Získaná emisní spektra z tepelného záchytu neutronu nejprve energeticky okalibrujeme, poté provedeme účinnostní kalibraci a po dalším zpracování porovnáme naměřená data s výsledky teoretických simulací.1 Photon strength functions in terms of statistical approach to a nuclear decay describe the probability distribution of photon emission by given nucleus. They can be studied using two step gamma cascades. The two step gamma cascade method was firstly introduced in fifties of...

Research paper thumbnail of Surface band characters of the Weyl semimetal candidate material MoTe2 revealed by one-step angle-resolved photoemission theory

Research paper thumbnail of Single-crystal studies and electronic structure investigation of the room-temperature semiconductor NaMnAs

Physical Review B, 2022

We report synthesis of single crystalline NaMnAs, confirm its antiferromagnetic order and charact... more We report synthesis of single crystalline NaMnAs, confirm its antiferromagnetic order and characterise the sample by photoemission spectroscopy. The electronic structure was studied using optical transmittance, x-ray and ultraviolet spectroscopy and by theoretical modeling using local density approximation (LDA) extended to LDA+U when Heisenberg model parameters were determined. Optical transmittance measurement have confirmed the theoretical predictions that NaMnAs is a semiconductor. Also the Néel temperature was closer determined for the first time from temperature dependence of magnetization, in agreement with our Monte Carlo simulations.

Research paper thumbnail of Multidimensional XUV Photoemission Spectroscopy of 1T-TiTe2 for different crystal orientations

We performed extreme ultraviolet (21.7 eV) multidimensional angle-resolved photoemission spectros... more We performed extreme ultraviolet (21.7 eV) multidimensional angle-resolved photoemission spectroscopy for two different crystal orientations linked to each other by mirror symmetry, we isolate and identify the role of orbital texture in photoemission from the transition metal dichalcogenide 1T-TiTe$_2$. By comparing these experimental results with theoretical calculations based on both a quantitative one-step model of photoemission and an intuitive tight-binding model, we unambiguously demonstrate the link between the momentum-dependent orbital orientation and the emergence of strong intrinsic linear dichroism in the photoelectron angular distributions.

Research paper thumbnail of Signature of Hidden Orbital-Texture in Photoemission Time-Reversal Dichroism

arXiv: Materials Science, 2020

We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe$_2$ for different c... more We performed angle-resolved photoemission spectroscopy (ARPES) of bulk 2H-WSe$_2$ for different crystal orientations linked to each other by time-reversal symmetry. We introduce a new observable called time-reversal dichroism, which quantifies the modulation of the photoemission intensity upon effective time-reversal operation. We demonstrate that the hidden orbital-texture of the crystal's electronic structure leaves its imprint onto the time-reversal dichroism, due to multiple orbitals interference effects in photoemission. Our experimental results are in quantitative agreement with state-of-the-art fully relativistic calculations performed using the one-step model of photoemission. While spin-resolved ARPES probes the spin component of entangled spin-orbital texture in multiorbital systems, we demonstrate that time-reversal dichroism is sensitive to its orbital-texture counterpart.

Research paper thumbnail of Unveiling the orbital texture of 1T-TiTe2 using intrinsic linear dichroism in multidimensional photoemission spectroscopy

npj Quantum Materials, 2021

The momentum-dependent orbital character in crystalline solids, referred to as orbital texture, i... more The momentum-dependent orbital character in crystalline solids, referred to as orbital texture, is of capital importance in the emergence of symmetry-broken collective phases, such as charge density waves as well as superconducting and topological states of matter. By performing extreme ultraviolet multidimensional angle-resolved photoemission spectroscopy for two different crystal orientations linked to each other by mirror symmetry, we isolate and identify the role of orbital texture in photoemission from the transition metal dichalcogenide 1T-TiTe2. By comparing our experimental results with theoretical calculations based on both a quantitative one-step model of photoemission and an intuitive tight-binding model, we unambiguously demonstrate the link between the momentum-dependent orbital orientation and the emergence of strong intrinsic linear dichroism in the photoelectron angular distributions. Our results represent an important step towards going beyond band structure (eigenv...

Research paper thumbnail of Revealing Hidden Orbital Pseudospin Texture with Time-Reversal Dichroism in Photoelectron Angular Distributions

Physical Review Letters, 2020

Research paper thumbnail of Bulk and surface electronic states in the dosed semimetallic HfTe2

Research paper thumbnail of Bixbyite-Ta2N2O film prepared by HiPIMS and postdeposition annealing: Structure and properties

Journal of Vacuum Science & Technology A, 2020

Nb-doped TiO 2 coatings developed by high power impulse magnetron sputtering-chemical vapor depos... more Nb-doped TiO 2 coatings developed by high power impulse magnetron sputtering-chemical vapor deposition hybrid deposition process

Research paper thumbnail of Spin, time, and angle resolved photoemission spectroscopy on WTe2

Physical Review Research, 2020

Research paper thumbnail of Angle-resolved photoemission calculations of WTe2 compared to experiment

APPLIED PHYSICS OF CONDENSED MATTER (APCOM 2019), 2019

Molybdenum dichalcogenides are probably the most studied single layer TMDCs by virtue of being ap... more Molybdenum dichalcogenides are probably the most studied single layer TMDCs by virtue of being appealing for sundry possible applications suchlike transistors, diodes, solar cells or more fundamental studies of spin or valley pseudospin and their interactions. Tungsten-based counterparts are on the other hand evincing much stronger spin-orbit coupling due to which all the spin-related effects are more stable at room temperature and thus more feasible for application. WTe 2 , a type-II Weyl semimetal is in particular interesting due to having two pairs of spin-differentiated Weyl points above Fermi energy. We have conducted several experiments following the evolution of the band dispersion in the vicinity of X and Y points of the Brillouin zone of WTe 2 which is substantial for understanding the fundamental properties of the structure-property relation of the system. Ab-initio set of photoemission calculations was performed using SPR-KKR package and compared to experimental results.

Research paper thumbnail of Ramseyova teorie aneb příklady, které jsou pro počítač příliš složité

summary:Ramsey theory deals with problems asking for the minimum number of elements which guarant... more summary:Ramsey theory deals with problems asking for the minimum number of elements which guarantees a particular property. These include e.g. Party Problem, Happy End Problem or Van der Waerden Problem. Solving the problems of this kind is rather time-consuming for a computer, but the result can often be obtained by mathematical reasoning with pencil and paper. Ramsey theory was deeply developed by a famous Hungarian mathematician Pál Erdös