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M. V. Kartsovnik

Publications and source records attributed to M. V. Kartsovnik.

27 records · Page 2Linked to original sources
arXiv2005

Superconductivity in the charge-density-wave state of the organic metal α-(BEDT-TTF)2KHg(SCN)4

The superconducting transition in the layered organic compound α-(BEDT-TTF)_2KHg(SCN)_4 has been studied in the two hydrostatic pressure regimes where a charge-density wave is either present or completely suppressed. Within the charge-density-wave state the experimental results reveal a network of weakly coupled superconducting regions. This is especially seen in a strong enhancement of the measured critical field and the corresponding positive curvature of its temperature dependence. Further, it is shown that on lowering the pressure into the density-wave state traces of a superconducting phase already start to appear at a much higher temperature.

cond-mat.supr-con↗
arXiv2003

New Electronic Phase Transitions in α-(BEDT-TTF)2KHg(SCN)4

α-(BEDT-TTF)2KHg(SCN)4 is considered to be in the charge-density-wave (CDW) state below 8 K. We present new magnetoresistance data suggesting that the material undergoes a series of field-induced CDW (FICDW) transitions at pressures slightly exceeding the critical pressure Pc at which the zero-field CDW state is destroyed. Further, we argue that a novel kind of FICDW transitions, entirely determined by a superposition of the strong Pauli and quantizing orbital effects of magnetic field on the CDW wavevector, arises when the field is strongly tilted towards the conducting layers. These new transitions can take place even in the case of a relatively well nested Fermi surface. Finally we report on the superconducting (SC) state and its coexistence with the CDW in the title compound under quasi-hydrostatic pressure. Below Pc the material is most likely a heterogeneous SC/CDW mixture, with the SC phase persisting down to ambient pressure. The SC onset temperature appears to drastically increase upon entering the SC/CDW coexistence region.

cond-mat.str-el↗
arXiv2003

Orbital quantization in the high magnetic field state of a charge-density-wave system

A superposition of the Pauli and orbital coupling of a high magnetic field to charge carriers in a charge-density-wave (CDW) system is proposed to give rise to transitions between subphases with quantized values of the CDW wavevector. By contrast to the purely orbital field-induced density-wave effects which require a strongly imperfect nesting of the Fermi surface, the new transitions can occur even if the Fermi surface is well nested at zero field. We suggest that such transitions are observed in the organic metal $α$-(BEDT-TTF)$_2$KHg(SCN)$_4$ under a strongly tilted magnetic field.

cond-mat.str-el↗
arXiv2002

Slow oscillations of magnetoresistance in quasi-two-dimensional metals

Slow oscillations of the interlayer magnetoresistance observed in the layered organic metal $β$-(BEDT-TTF)$_2$IBr$_2$ are shown to originate from the slight warping of its Fermi surface rather than from independent small cyclotron orbits. Unlike the usual Shubnikov-de Haas effect, these oscillations are not affected by the temperature smearing of the Fermi distribution and can therefore become dominant at high enough temperatures. We suggest that the slow oscillations are a general feature of clean quasi-two-dimensional metals and discuss possible applications of the phenomenon.

cond-mat↗
arXiv2001

Shubnikov-de Haas effect in quasi-two-dimensional compounds

The Shubnikov - de Haas effect in quasi-two-dimensional compounds is studied. The conductivity is calculated from the Kubo formula. Two effects -- the field-dependent phase shift of the beats and the slow oscillations of the conductivity are explained and calculated. The results are applicable to the strongly anisotropic organic metals and other layered compounds.

cond-mat.stat-mech↗
arXiv2001

Anomalous beating phase of the oscillating interlayer magnetoresistance in layered metals

We analyze the beating behavior of the magnetic quantum oscillations in a layered metal under the conditions when the cyclotron energy $\hbar ω_c $ is comparable to the interlayer transfer energy $t$. We find that the positions of the beats in the interlayer resistance are considerably shifted from those in the magnetization oscillations, and predict that the shift is determined by the ratio $\hbar ω_c/t$. A comparative study of the Shubnikov-de Haas and de Haas-van Alphen effects in the quasi-two-dimensional organic metal $β$-(BEDT-TTF)$_2$IBr$_2$ appears to be consistent with the theoretical prediction.

cond-mat.stat-mech↗
arXiv2001

Orbital effect of a magnetic field on the low temperature state in the organic metal $α$-(BEDT-TTF)$_2$KHg(SCN)$_4$

The effect of pressure on the B--T phase diagram of $α$-(BEDT-TTF)$_2$KHg(SCN)$_4$ is studied. The measured phase lines can be well described by a recent model of a charge-density wave system with varying nesting conditions. A remarkable increase of the transition temperature with magnetic field is found in a certain pressure and field range. We associate this result with a dramatic enhancement of the orbital effect of magnetic field due to a deterioration of the nesting conditions by pressure. Furthermore, we present data which can be interpreted as a first sign of field-induced charge-density waves.

cond-mat.str-el↗