Aichhorn, M., Saha-Dasgupta, T., Valenti, R., Glawion, S., Sing, M., Claessen, R.
We present results for the single-particle spectral function of the low-dimensional system TiOCl in the insulating state. We show by a combination of ab initio Density Functional Theory (DFT) and...
New structural and magnetic aspects of the nanotube system Na2V3O7 (2008)
Zaharko, O., Gavilano, J. L., Straessle, Th., Miclea, C. F., Mota, A. C., Filinchuk, Y., ...
We present new experimental results of low temperature x-ray synchrotron diffraction, neutron scattering and very low temperature (mK-range) bulk measurements on the nanotube system ${\tube}$. The...
Kent, P. R. C., Saha-Dasgupta, T., Jepsen, O., Andersen, O. K., Macridin, A., Maier, T. A., ...
Using a combined local density functional theory (LDA-DFT) and quantum Monte Carlo (QMC) dynamic cluster approximation approach, the parameter dependence of the superconducting transition temperature...
Das, Hena, Waghmare, Umesh V., Saha-Dasgupta, T., Sarma, D. D.
Using first-principles density functional calculations, we study the electronic and magnetic properties of ferromagnetic insulating double-perovskite compound La2NiMnO6, which has been reported to...
Ikeda, M., Yoshida, T., Fujimori, A., Kubota, M., Ono, K., Das, Hena, ...
We have performed angle-resolved photoemission spectroscopy (ARPES) measurements and first-principles electronic structure calculations on the electron-doped high-Tc superconductors Ln1.85Ce0.15CuO4...
Structure, bonding and magnetism in cobalt clusters (2007)
Datta, S., Kabir, M., Ganguly, S., Sanyal, B., Saha-Dasgupta, T., Mookerjee, A.
The structural, electronic and magnetic properties of Co$_n$ clusters ($n=2-$20) have been investigated using density functional theory within the pseudopotential plane wave method. An unusual...
Proposed low energy model Hamiltonian for spin-gapped system CuTe2O5 (2007)
Das, Hena, Saha-Dasgupta, T., Gros, Claudius, Valenti, Roser
Using first-principles electronic structure calculations based on the Nth order muffin tin orbital (NMTO)-downfolding technique, we derived the low-energy spin model for CuTe2O5. Our study reveals...
Effects of Two Energy Scales in Weakly Dimerized Antiferromagnetic Quantum Spin Chains (2007)
Brühl, A., Wolf, B., Pashchenko, V., Anton, M., Gross, C., Assmus, W., ...
By means of thermal expansion and specific heat measurements on the high-pressure phase of (VO)$_2$P$_2$O$_7$, the effects of two energy scales of the weakly dimerized antiferromagnetic $S$ = 1/2...
Poteryaev, A. I., Tomczak, J. M., Biermann, S., Georges, A., Lichtenstein, A. I., Rubtsov, A. N., ...
We present a study of the paramagnetic metallic and insulating phases of vanadium sesquioxide by means of the $N$th order muffin-tin orbital implementation of density functional theory combined with...
Theoretical study of doped $Tl_2Mn_2O_7$ and $Tl_2Mn_2O_7$ under pressure (2007)
Raychaudhury, Molly De, Saha-Dasgupta, T, Sarma, DD
Using first-principles density-functional-based calculations, we study the effect of doping and pressure on the manganese-based pyrochlore compound, $Tl_2Mn_2O_7$, which exhibits colossal...
Theoretical study of doped $Tl_2Mn_2O_7$ and $Tl_2Mn_2O_7$ under pressure (2007)
Raychaudhury, Molly De, Saha-Dasgupta, T, Sarma, DD
Using first-principles density-functional-based calculations, we study the effect of doping and pressure on the manganese-based pyrochlore compound, $Tl_2Mn_2O_7$, which exhibits colossal...
Theoretical study of doped-Tl$_{2}$Mn$_{2}$O$_{7}$ and Tl$_{2}$Mn$_{2}$O$_{7}$ under pressure (2006)
De Raychaudhury, Molly, Saha-Dasgupta, T., Sarma, D. D.
Using first-principles density functional based calculations, we study the effect of doping and pressure in manganese based pyrochlore compound,Tl$_{2}$Mn$_{2}$O$_{7}$ that exhibits colossal...
Cluster Dynamical Mean-field calculations for TiOCl (2006)
Saha-Dasgupta, T., Lichtenstein, A., Hoinkis, M., Glawion, S., Sing, M., Claessen, R., ...
Based on a combination of cluster dynamical mean field theory (DMFT) and density functional calculations, we calculated the angle-integrated spectral density in the layered $s=1/2$ quantum magnet...
Valenti, R., Saha-Dasgupta, T., Jeschke, H. O., Rahaman, B., Rosner, H., Lemmens, P., ...
We present a comparative study of the coupled-tetrahedra quantum spin systems Cu2Te2O5X2, X=Cl, Br (Cu-2252(X)) and the newly synthesized Cu4Te5O12Cl4 (Cu-45124(Cl)) based on ab initio Density...
Rahaman, Badiur, Jeschke, Harald O., Valenti, Roser, Saha-Dasgupta, T.
We present a microscopic study of the electronic and magnetic properties of the newly synthesized Cu(II)-spin tetrahedron-based Cu4Te5O12Cl4 compound based on Density Functional calculations and on...
Origin of Ferromagnetism and its pressure and doping dependence in Tl$_{2}$Mn$_{2}$O$_{7}$ (2006)
Saha-Dasgupta, T., De Raychaudhury, Molly, Sarma, D. D.
Using NMTO-{\it downfolding} technique, we explore and establish the origin of ferromagnetism in the pyrochlore system, Tl$_{2}$Mn$_{2}$O$_{7}$. It is found to be driven by hybridization induced...
Unusual quasi-one-dimensional electron dispersions in the spin-1/2 quantum magnet TiOCl (2005)
Hoinkis, M., Sing, M., Schaefer, J., Klemm, M., Horn, S., Benthien, H., ...
We have studied the electronic structure of the spin-1/2 quantum magnet TiOCl by polarization-dependent momentum-resolved photoelectron spectroscopy. From that, we confirm the quasi-one-dimensional...
Spin gap formation in the quantum spin systems TiOX, X=Cl and Br (2005)
Lemmens, P., Choi, K. Y., Valenti, R., Saha-Dasgupta, T., Abel, E., Lee, Y. S., ...
In the layered quantum spin systems TiOCl and TiOBr the magnetic susceptibility shows a very weak temperature dependence at high temperatures and transition-induced phenomena at low temperatures....
Spin gap formation in the quantum spin systems TiOX, X=Cl and Br (2005)
Lemmens, P., Choi, K. Y., Valentí, R., Saha-Dasgupta, T., Abel, E., Lee, Y. S., ...
Correlation effects on the electronic structure of TiOCl: a NMTO+DMFT study (2004)
Saha-Dasgupta, T., Lichtenstein, A., Valenti, R.
Using the recently developed N-th order muffin-tin orbital-based downfolding technique in combination with the Dynamical Mean Field theory, we investigate the electronic properties of the much...
Na2V3O7, a frustrated nanotubular system with spin-1/2 diamond rings (2004)
Saha-Dasgupta, T., Valenti, Roser, Capraro, F., Gros, C.
Following the recent discussion on the puzzling nature of the interactions in the nanotubular system Na2V3O7, we present a detailed ab-initio microscopic analysis of its electronic and magnetic...
TiOCl, an orbital-ordered system? (2003)
Saha-Dasgupta, T., Valenti, Roser, Rosner, H., Gros, Claudius
We present first principles density functional calculations and downfolding studies of the electronic and magnetic properties of the layered quantum spin system TiOCl. We discuss explicitely the...
Role of c-axis pairs in V2O3 from the band-structure point of view (2003)
Elfimov, I. S., Saha-Dasgupta, T., Korotin, M. A.
The common interpretation of the LDA band structure of V$_{2}$O$_{3}$ is that the apparent splitting of the $a_{1g}$ band into a low intensity structure deep below the Fermi energy and a high...
Halogen-mediated exchange in the coupled-tetrahedra quantum spin systems Cu2Te2O5X2 (X=Br,Cl) (2003)
Valenti, Roser, Saha-Dasgupta, T., Gros, Claudius, Rosner, H.
Motivated by recent discussion on possible quantum critical behavior in the coupled Cu-tetrahedra system Cu2Te2O5Br2, we present a comparative ab initio study of the electronic properties of...
Third-generation muffin-tin orbitals (2003)
Andersen, O. K., Saha-Dasgupta, T., Ezhov, S.
By the example Of sp(3)-bonded semiconductors, we illustrate what 3rd-generation muffin-tin orbitals (MTOs) are. We demonstrate that they can be downfolded to smaller and smaller basis sets:...
Nguyen-Manh, D., Saha-Dasgupta, T., Andersen, O. K.
The third-generation LMTO method provides a new wave function basis set in which the energy dependence of the interstitial region and inside muffin-tin (MT) spheres is treated on an equal footing....
Ab initio investigation of VOSeO3, a spin gap system with coupled spin dimers (2002)
Valenti, Roser, Saha-Dasgupta, T., Mila, F.
Motivated by an early experimental study of VOSeO3, which suggested that it is a quasi-2D system of weakly coupled spin dimers with a small spin gap, we have investigated the electronic structure of...
Comparative study between two quantum spin systems KCuCl$_{3}$ and TlCuCl$_{3}$ (2002)
Saha-Dasgupta, T., Valenti, R.
We have performed an {\it ab initio} study of the electronic structure of two isostructural quantum spin systems, KCuCl$_{3}$ and TlCuCl$_{3}$, which have recently attracted much attention due to...
Third-generation muffin-tin orbitals (2002)
Andersen, O. K., Saha-Dasgupta, T., Ezhov, S.
By the example of sp^3-bonded semiconductors, we illustrate what 3rd-generation muffin-tin orbitals (MTOs) are. We demonstrate that they can be downfolded to smaller and smaller basis sets:...
Nature of the spin-singlet ground state in CaCuGe2O6 (2002)
Valenti, Roser, Saha-Dasgupta, T., Gros, Claudius
We investigate by means of ab initio electronic structure analysis and Quantum Monte Carlo calculations the scenario where longer-ranged magnetic interactions dominate over short-ranged interactions...
Electronic and magnetic structure of CsV$_2$O$_5$ (2001)
Valenti, Roser, Saha-Dasgupta, T.
We have studied the electronic structure of the spin-gapped system CsV$_2$O$_5$ by means of an ab initio calculation. Our analysis and a re-examination of the susceptibility data indicate that the...
Mazurenko, V. V., Lichtenstein, A. I., Katsnelson, M. I., Dasgupta, I., Saha-Dasgupta, T., Anisimov, V. I.
The nature of insulating state driven by electronic correlations in the quarter-filled ladder compound $\alpha'$NaV$_{2}$O$_{5}$ is investigated within a cluster dynamical mean-field approach. An...
Saha-Dasgupta, T., Sarma, D. D.
We have investigated the electronic structure of ordered and disordered Sr$_2$FeMoO$_6$ using {\it ab-initio} band structure methods. The effect of disorder was simulated within super-cell...
Modeling the electronic behavior of $\gamma$-LiV2O5: a microscopic study (2001)
Valenti, R., Saha-Dasgupta, T., Alvarez, J. V., Pozgajcic, K., Gros, C.
We determine the electronic structure of the one-dimensional spin-1/2 Heisenberg compound $\gamma$-LiV$_2$O$_5$, which has two inequivalent vanadium ions, V(1) and V(2), via density-functional...
Band-Structure Trend in Hole-Doped Cuprates and Correlation with Tcmax (2001)
Pavarini, E., Dasgupta, I., Saha-Dasgupta, T., Jepsen, O., Andersen, O. K.
Band-structure trend in hole-doped cuprates and correlation with Tcmax (2000)
Pavarini, E., Dasgupta, I., Saha-Dasgupta, T., Jepsen, O., Andersen, O. K.
By calculation and analysis of the bare conduction bands in a large number of hole-doped high-temperature superconductors, we have identified the energy of the so-called axial-orbital as the...
Muffin Tin Orbitals of Arbitrary Order (2000)
Andersen, O. K., Saha-Dasgupta, T.
We have derived orbital basis sets from scattering theory. They are expressed as polynomial approximations to the energy dependence of a set of partial waves, in quantized form. The corresponding...
Electronic Structure of Sr_2FeMoO_6 (2000)
Sarma, D. D., Mahadevan, Priya, Saha-Dasgupta, T., Ray, Sugata, Kumar, Ashwani
We have analysed the unusual electronic structure of Sr_2FeMoO_6 combining ab-initio and model Hamiltonian approaches. Our results indicate that there are strong enhancements of the intraatomic...
Developing the MTO formalism (2000)
Andersen, O. K., Saha-Dasgupta, T., Tank, R. W., Arcangeli, C., Jepsen, O., Krier, G.
Electronic structure and exchange interactions of the ladder vanadates CaV2O5 and MgV2O5 (2000)
Korotin, M. A., Anisimov, V. I., Saha-Dasgupta, T., Dasgupta, I.
Electronic structure and exchange interactions of the ladder vanadates CaV2O5 and MgV2O5 (1999)
Korotin, M. A., Anisimov, V. I., Saha-Dasgupta, T., Dasgupta, I.
We have performed ab-initio calculations of the electronic structure and exchange couplings in the layered vanadates CaV2O5 and MgV2O5. Based on our results we provide a possible explanation of the...
Developing the MTO Formalism (1999)
Andersen, O. K., Saha-Dasgupta, T., Tank, R. W., Arcangeli, C., Jepsen, O., Krier, G.
We review the simple linear muffin-tin orbital method in the atomic-spheres approximation and a tight-binding representation (TB-LMTO-ASA method), and show how it can be generalized to an accurate...
Third-Generation TB-LMTO (1998)
Andersen, O. K., Arcangeli, C., Tank, R. W., Saha-Dasgupta, T., Krier, G., Jepsen, O., ...
We describe the screened Korringa-Kohn-Rostoker (KKR) method and the third-generation linear muffin-tin orbital (LMTO) method for solving the single-particle Schroedinger equation for a MT potential....
Electronic Structure of Ladder Cuprates (1998)
Muller, T. F. A., Anisimov, V., Rice, T. M., Dasgupta, I., Saha-Dasgupta, T.
We study the electronic structure of the ladder compounds (SrCa)CuO 14-24-41 and SrCuO 123. LDA calculations for both give similar Cu 3d-bands near the Fermi energy. The hopping parameters estimated...